awesome-x402

# Awesome X402 [](https://awesome.re) > ⚡ **The Ultimate x402 Resource Hub** - Everythng you need to build internet-native payments using HTTP 402. Perfect for AI agents, APIs, and micropayments. Build paywalls, monetize services, and enable autonomous agent payments with crypto/USDC. Zero fees, 2-second settlement. [](https://github.com/xpaysh/awesome-x402) ## Contents - [🎯 Quick Start - Become an x402 Champion](#-quick-start---become-an-x402-champion) - [📚 Official Resources](#-official-resources) - [📖 Protocol Documentation](#-protocol-documentation) - [🚀 Quickstart Guides](#-quickstart-guides) - [⚙️ Protocol Implementations](#-protocol-implementations) - [🏭 Production Implementatdions](#-production-implementations) - [🛠️ SDKs & Client Libraries](#-sdks--client-libraries) - [🔧 Server Frameworks & Middleware](#-server-frameworks--middleware) - [🏗️ Facilitators](#-facilitators) - [💡 Example Applications](#-example-applications) - [🎨 Use Cases & Patterns](#-use-cases--patterns) - [🤖 AI Agent Integration](#-ai-agent-integration) - [Octodamus](https://api.octodamus.com) — AI market-intelligence API for agents. 33 pay-per-call x402 endpoints on Base ($0.01–$0.02, USDC, no keys): cross-venue derivatives facts, prediction-market odds, congressional trades, macro reference numbers, and a tokenized-equity suite (24/7 fair value, on-chain basis, and Arcus perp facts for Robinhood Chain). Ed25519-signed responses, MCP server, all endpoints cataloged in the CDP x402 Bazaar. ([llms.txt](https://octodamus.com/llms.txt)) ([Discovery](https://api.octodamus.com/.well-known/x402.json)) ([MCP](https://smithery.ai/server/octodamusai/market-intelligence)) - [🔨 Tools & Utilities](#-tools--utilities) - [🧪 Testing & Development](#-testing--development) - [📚 Tutorials & Learning Resources](#-tutorials--learning-resources) - [🎥 Videos & Talks](#-videos--talks) - [📝 Articles & Blog Posts](#-articles--blog-posts) - [👥 Community](#-community) - [🌟 Ecosystem Projects](#-ecosystem-projects) - [📊 Ecosystem Market Data](#-ecosystem-market-data) - [🚀 Migration Guides](#-migration-guides) - [🔒 Security & Audits](#-security--audits) - [🔗 Related Protocols](#-related-protocols) - [🤝 Contributing](#-contributing) - [Awesome Lists](#awesome-lists) The x402 protocol enables instant Blockchain payments over HTTP using the 402 "Payment Required" status code. This is your complete guide to mastering x402 and building the future of agent payments. 🚀 **Start building in 5 minutes** | ⚡ **2-second settlement** | 💰 **USDC on Base** --- ## 🎯 Quick Start - Become an x402 Champion **New to x402?** Follow this path to mastery: 1. [5-Minute Quickstart](https://docs.cdp.coinbase.com/x402/quickstart-for-sellers) - Accept your first payment. 2. Choose Your Stack - Find your language/framework. 3. Copy an Example - Working code you can run immediately. 4. Join the Community - Get help from other builders. **For AI Agents:** Start with [MCP Integration](#model-context-protocol-mcp) to enable Claude/other agents to make autonomous payments. --- ## 📚 Official Resources Core resources from the x402 protocol maintainers. - [x402 Protocol Specification](https://github.com/coinbase/x402) - Official open-source protocol implementation by Coinbase. - [x402 Foundation](https://x402.org) - Protocol foundation website with overview and documentation. - [x402 Whitepaper](https://x402.org/x402-whitepaper.pdf) - Technical deep dive into protocol architecture. - [Coinbase Developer Platform Docs](https://docs.cdp.coinbase.com/x402) - Complete implementation guide and API reference. - [Protocol Specifications](https://github.com/coinbase/x402/tree/main/specs) - Detailed technical specifications. - [Payment Schemes](https://github.com/coinbase/x402/tree/main/specs/schemes) - Different payment flow types. - [EVM Implementation](https://github.com/coinbase/x402/blob/main/specs/schemes/exact/scheme_exact_evm.md) - Ethereum Virtual Machine specifics. ## 📖 Protocol Documentation Essential documentation for understanding and implementing x402. - [How x402 Works](https://docs.cdp.coinbase.com/x402/how-it-works) - Complete payment flow explanation with diagrams. - [Payment Requirements Schema](https://github.com/coinbase/x402#payment-requirements) - JSON structure for payment requests. - [Payment Payload Format](https://github.com/coinbase/x402#payment-payload) - Client payment submission format. - [Verification & Settlement](https://github.com/coinbase/x402#verification-and-settlement) - Payment validation process. - [EIP-3009 TransferWithAuthorization](https://eips.ethereum.org/EIPS/eip-3009) - Gasless transfer standard used by x402. - [HTTP 402 Status Code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/402) - The long-dormant HTTP status. ## 🚀 Quickstart Guides Get started with x402 in minutes. - 5-Minute Quickstart for Sellers - Accept your first payment. - [Buyer/Client Setup](https://docs.cdp.coinbase.com/x402/quickstart-buyers) - Make automated payments. - [One-Line Integration](https://github.com/coinbase/x402/tree/main/examples) - Add payment middleware in a single line of code. - [Base Sepolia Testnet Setup](https://docs.cdp.coinbase.com/x402/network-support) - Get test USDC and start testing. - Production Deployment Checklist - Go live on Base mainnet. ## ⚙️ Protocol Implementations Official and community implementations of the x402 protocol. ### Go - [coinbase/x402](https://github.com/coinbase/x402/tree/main/go) ⭐ **Official** - Complete Go implementation. - Core protocol types and utilities - Payment verification and settlement logic - Multi-chain support (Base, Base Sepolia, Ethereum, Solana) ### TypeScript/JavaScript - [x402-typescript](https://github.com/coinbase/x402/tree/main/typescript) ⭐ **Official** - Complete TypeScript implementation. - Core protocol types and utilities - Payment verification and settlement logic - Multi-chain support (Base, Base Sepolia, Ethereum, Solana) - [x402-data-api](https://github.com/155143783/x402-data-api) - HTTP 402 micro-payment data API with Base chain USDC payments. 16 developer data tools including email validation, DNS lookup, WHOIS, SSL check, and IP geolocation with x402 payment integration. - [x402-express](https://github.com/coinbase/x402/tree/main/examples/typescript/servers/express) - Express.js middleware example. - [hive-rosetta](https://www.npmjs.com/package/hive-rosetta) ⭐ **Community** - Open EIP-3009 `transferWithAuthorization` signer. Zero ethers/web3 dependency, primitives-only EIP-712. Returns wire shape `{scheme: 'exact', network: 'eip155:8453', payload: {authorization, signature}}`. Same package name on PyPI. ([GitHub](https://github.com/srotzin/hive-rosetta)) ### Python - [x402](https://pypi.org/project/x402/) ⭐ **Official** - Python SDK on PyPI. - FastAPI middleware integration - Requests session with auto-payments - Payment requirement generation - [ag402](https://github.com/AetherCore-Dev/ag402) ⭐ **Community** - Payment layer for AI agents using x402. Wrap any API or MCP server with a USDC paywall (`ag402 serve`), or let agents auto-pay (`ag402 run`). Solana USDC, ~0.5s settlement, non-custodial, 648+ tests. [Glama](https://glama.ai/mcp/servers/AetherCore-Dev/ag402-mcp) - [x402-pay](https://pypi.org/project/x402-pay/) - Call any x402 API with one API key. Routes requests through a broker that handles on-chain payment. httpx-based, optional wallet mode for direct payments. ([GitHub](https://github.com/bartonguestier1725-collab/x402-pay)) - [hive-rosetta](https://pypi.org/project/hive-rosetta/) ⭐ **Community** - Direct port of the Node `hive-rosetta` signer. Byte-identical EIP-712 digest across both languages. Returns `{scheme, network, payload}` matching CDP `/verify` and `/settle`. ([GitHub](https://github.com/srotzin/hive-rosetta)) ### Rust - [x402-rs](https://github.com/x402-rs/x402-rs) ⭐ **Community** - Production-grade Rust implementation. - Axum middleware - Reqwest client wrapper - Self-hostable facilitator - Multi-chain support - x402-axum - Axum web framework integration. - x402-reqwest - Reqwest HTTP client wrapper. ## 🏭 Production Implementations Real companies using x402 in production with proven scale and transaction volumes. - [AfaAgent x402 API Suite](https://afaagent-x402-api.storm-fly.workers.dev) - 43 production-grade x402 APIs (DeFi, wallet security, AI/ML, developer tools, SEO) with pay-per-call USDC micropayments on Base. Includes MCP server with 43 tools (Streamable HTTP), OpenAPI 3.0 spec, llms.txt, and agents.json for AI-agent discovery. Premium services up to .99/call. ([Discovery](https://afaagent-x402-api.storm-fly.workers.dev/.well-known/x402) | [MCP](https://afaagent-x402-api.storm-fly.workers.dev/mcp) | [GitHub](https://github.com/AfaAgent/x402-api-suite)) - [Langston Search](https://langston.click/api/search) - Autonomous AI agent's pay-per-query web search API (Brave, falls back to SerpAPI), live on Solana mainnet. 0.02 USDC per query via x402 exact scheme. ([Discovery](https://langston.click/.well-known/x402)) ### High-Volume Production Deployments - [Kaisha — Japan Company Registry API](https://kaisha-api.hp-vladic.workers.dev) - Official-registry data for all 5.76M Japanese corporations + 5.05M invoice registrations from National Tax Agency open data: resolve company names / corporate numbers (法人番号) to registry records, verify Japan invoice registration numbers (適格請求書/T+13-digit) against the NTA dataset, and compute Japanese business days & national holidays. $0.002–$0.01 USDC per call on Base & Solana via CDP facilitator. No API keys. MCP: `npx -y kaisha-mcp`. ([OpenAPI](https://kaisha-api.hp-vladic.workers.dev/openapi.json) | [llms.txt](https://kaisha-api.hp-vladic.workers.dev/llms.txt) | [Discovery](https://kaisha-api.hp-vladic.workers.dev/.well-known/x402) | [x402scan](https://www.x402scan.com/server/a3937fba-de2e-41e6-b57b-048132e91d0a) | [npm](https://www.npmjs.com/package/kaisha-mcp) | [GitHub](https://github.com/vladic-corp/kaisha-api)) - [MoneyMachine x402 Suite](https://github.com/itsmeadamdamroma/money-machine-x402) - Agent-payable APIs on Base USDC: **GigRadar** (Superteam/r/forhire/HN/Freelancer gigs $0.15), **LightHouse-lite** web vitals ($0.12), **DocClerk** PDF field extract ($0.25), CrawlJudge ($0.03), Axe-lite a11y ($0.08), HTML scrape ($0.05). Self-facilitator, open source. PayTo `0x5Cc3c4E5020Ec3D81E392658eFe7b27966872CE7`. - [J-sey Data API](https://jsey.dpdns.org) - Pay-per-call data API on Base with 18 endpoints for wallet lookups, web scraping, crypto prices, and DeFi yields; $0.002 per call via x402. - [Fleet x402 Microservices](https://fleet-x402-audit.fly.dev) - Two agent-payable AI services on Base: SEO Audit ($0.05 USDC) and Competitive Intel Pack ($0.50 USDC). Instant response, zero auth required, machine-readable JSON. ([Discovery](https://fleet-x402-audit.fly.dev/.well-known/x402-listing)) - [Arch Tools](https://archtools.dev) - 58 production API tools for AI agents with x402 payments built in. Web scraping, AI generation, crypto data, OCR, browser automation, MCP compatible. Patent-pending agent auth. 15+ chains supported. ([GitHub](https://github.com/Deesmo/Arch-AI-Tools)) - [Bounty API](https://bountyapi.com) - Agent-native API marketplace with x402 micropayments. 7 live endpoints. Free + paid ($0.005-0.01 USDC on Base). MCP: npx bountyapi-mcp. Verified on-chain. (GitHub: vncent786/bounty-api) - [PayAPI Market](https://payapi.market) - First marketplace for x402-powered APIs. 10 APIs, 65 endpoints: UK property data, email verification, company enrichment, postcode lookup, currency/crypto rates, screenshots, DNS intelligence, web scraping, IP geolocation, QR codes. $0.001–$0.01 USDC on Base per request. MCP server discovery. ([GitHub](https://github.com/chetparker/x402-marketplace)) - [LogicNodes](https://logicnodes.io) - Live A2A marketplace with 619 deterministic microservices payable per-call in USDC. No signup — agents pay via x402, results include SHA-256 trust hashes. 8 chains: Base, Solana, Arc, Arbitrum, Optimism, Polygon, Ethereum, World Chain. Tiers: Micro $0.001 · Basic $0.05 · Standard $0.15 · Premium $0.50 USDC. MCP: `npx @logicnodez/mcp-bridge` | Python: `pip install logicnodes-m2m`. ([npm](https://www.npmjs.com/package/@logicnodez/mcp-bridge)) | ([PyPI](https://pypi.org/project/logicnodes-m2m/)) | ([Agent Guide](https://logicnodes.io/agent-guide)) | ([llms.txt](https://logicnodes.io/llms.txt)) - [JarvisClaw](https://api.jarvisclaw.ai) - x402 payment gateway bridging 200+ LLM providers (OpenAI, Anthropic, Google, DeepSeek, etc.) to on-chain USDC micropayments on Base. HD wallet per-user isolation, real-time exchange-rate pricing, three-tier caching marketplace, circuit breaker fault tolerance, and multi-chain fallback. Pay-per-token with sub-cent granularity — no API keys, no subscriptions. MCP-native with intent resolution for autonomous agents. ([Docs](https://docs.jarvisclaw.ai)) | ([SDK: Python](https://pypi.org/project/jarvisclaw/)) | ([SDK: Go](https://pkg.go.dev/github.com/api-jarvisclaw/go-sdk)) - [Superhighway](https://superhighway.walls.sh) - Web search API for AI agents, live in production on Base mainnet. Five tools: search, news, images, scrape, and one-call deep research. $0.001 USDC per call. MCP-compatible: `npx -y superhighway-mcp`. Free API key available. - [Rug Munch Intelligence](https://x402.rugmunch.io) - 117 MCP tools + 19 REST API endpoints for crypto data: DexScreener, Birdeye, GMGN, Arkham, Nansen, Dune, Jupiter, DeFiLlama, and more. $0.001-$0.02 USDC per call. Multi-chain (Base + Solana), free trial (1 call/IP), OpenAPI spec, no API keys, no signup. ([Discovery](https://x402.rugmunch.io/.well-known/x402) | [OpenAPI](https://x402.rugmunch.io/openapi.json) | [MCP Catalog](https://x402.rugmunch.io/mcp) | [Solana](https://x402-sol.rugmunch.io/.well-known/x402) | [GitHub](https://github.com/Rug-Munch-Media-LLC/)) - [AIsa](https://aisa.network) - Leading x402 payment processor with **10.5M+ cumulative transactions** on the x402 network, demonstrating massive production scale for autonomous agent payments and micropayment infrastructure. - [Bitget](https://www.bitget.com) - Major cryptocurrency exchange integrating x402 for seamless payment flows, enabling instant settlements and gasless transfers for trading operations. - [AI Rook — Trading Intelligence + General Agent APIs](https://agents.ai-rook.com) — 22 endpoints across 4 categories: trading intelligence (market pulse, trade signals, order flow, liquidation heatmap, AI chart analysis, backtests, smart money), web utilities (web-fetch, search, screenshot, IP lookup, email validate, QR, PDF extract, domain lookup), AI inference (summarize, extract-data, classify via Queen MiniMax M2.7 456B MoE), image generation (FLUX.2-klein). Pay-per-call $0.002–$2.00 USDC on Base via x402-atm v3.0. No API keys. No signup. EscrowV2 onchain settlement. ([OpenAPI](https://agents.ai-rook.com/openapi.json) | [x402 manifest](https://agents.ai-rook.com/.well-known/x402.json) | [MCP tools](https://agents.ai-rook.com/mcp/tools)) - [Stratalize](https://www.stratalize.com) — 100+ attested financial, healthcare, real estate, and governance intelligence tools with x402 micropayments on Base. Ed25519-signed outputs on every synthesis. $0.02–$1.00 USDC per tool call. MCP registry: com.stratalize. ([x402.json](https://www.stratalize.com/.well-known/x402.json)) - [Coinbase Developer Platform](https://coinbase.com/developer-platform) - Official CDP implementation processing hundreds of thousands of transactions weekly with enterprise-grade reliability and 2-second settlement times. - [Cloudflare Workers](https://workers.cloudflare.com) - Edge computing platform with x402 integration serving global distributed payment verification at scale across 300+ data centers. - [GigSoul AI Research Agent](https://gig-x402-api.jayson-be1.workers.dev) - 23-endpoint AI research API for consultants: SEC filings, earnings calls, competitor analysis, market research, and document intelligence. - [Cloudflare Workers](https://workers.cloudflare.com) - Edge computing platform with x402 integration serving global distributed payment verification at scale across 300+ data centers..01 USDC per call on Base mainnet. Wallet: x2b6c16fb557291b98222a570526ff2430848b723. ([OpenAPI](https://gig-x402-api.jayson-be1.workers.dev/openapi.json) | [.well-known/x402.json](https://gig-x402-api.jayson-be1.workers.dev/.well-known/x402.json)) - [Zuluworks AI — Sovereign Shaka PQC-Shield Factory](https://api.zuluworksai.com) - Autonomous A2A factory on Cloudflare Workers selling 5 post-quantum-hardened agent services via x402 USDC on Base L2: `quantum-shield` ($0.10, ML-KEM-768 PQC tunnel — NIST FIPS 203), `kya` ($0.01, agent trust scoring), `browser-rendering` ($0.03, headless browser extraction), `memory` ($0.05, semantic recall on a PQC knowledge index), `workers-ai` ($0.02, Llama 3.1 inference). All settlement routed through Coinbase CDP facilitator for Bazaar indexing. ([Agent Card](https://api.zuluworksai.com/.well-known/agent.json) | [Bazaar Manifest](https://api.zuluworksai.com/.well-known/x402-bazaar.json) | [MCP](https://api.zuluworksai.com/.well-known/mcp.json) | [Sitemap](https://api.zuluworksai.com/sitemap.xml)) - **[Suede Agent Studio](https://agents.suedeai.ai)** - Visual agent-flow builder that publishes flows as pay-per-call x402 endpoints (USDC on Base). Machine-readable catalog at [`/api/catalog`](https://agents.suedeai.ai/api/catalog); each agent exposes `/.well-known/x402`, `/.well-known/agent-card`, and `/a2a`. Two live agents: Daily Lyric Drop ($0.10 USDC) and The Ownership Loop ($0.25 USDC). - [Satelink RPC](https://rpc.satelink.network) - Pay-per-call blockchain RPC for agents: one $0.10 USDC settlement on Base buys a 1,000-call Polygon JSON-RPC bundle — no signup, no subscription. HTTP 402-native with spec-compliant payment requirements past the free tier (500 calls/day/IP); wallet-signature registration for prepaid credits at $0.00003/call. Machine-readable manifest, live pricing, market comparison and capability APIs. ([Manifest](https://rpc.satelink.network/.well-known/satelink.json) | [Pricing](https://rpc.satelink.network/v1/pricing) | [Compare](https://rpc.satelink.network/v1/compare)) - [Agent402](https://agent402.tools) - Open-source, self-hostable x402 + MCP server with ~1,100 deterministic web tools: browser rendering, web search, PDF/image/OCR/audio, geo, live data (FX, weather, USGS, gov-data), network truth (DNS/TLS/WHOIS), crypto/x402 helpers, ~1,040 pure-CPU utilities. Dual-rail: free via proof-of-work, paid via USDC on Base/Polygon/Arbitrum (x402 v2 with Bazaar discovery). No LLM in the serving path — every tool re-tested against its own example before each release. Ships a hosted MCP connector (`/mcp`), an open x402 index ([Find](https://agent402.tools/api/find) · [Route](https://agent402.tools/api/route) · [Leaderboard](https://agent402.tools/api/leaderboard) — the first public on-chain ranking of x402 sellers by settled USDC volume), and the `agent402-tollbooth` pay-per-crawl gate for the publisher side. MIT. ([MCP](https://agent402.tools/mcp)) ([OpenAPI](https://agent402.tools/openapi.json)) ([Discovery](https://agent402.tools/.well-known/x402)) ([GitHub](https://github.com/MikeyPetrillo/Agent402)) - [Asset Forge](https://asset-forge-hire.vercel.app/) - Vercel-serverless micro-API for AI agents that returns SVG OG cards, robots.txt + sitemap.xml + llms.txt bundles, initials avatars, and shields-style status badges. Six endpoints including `/api/payment-required` that publishes an x402-spec at runtime. USDC paid on Base at $0.01 per call (recipient `0x833ca7dcdb6a681ddc0c15982ef0d609bceb3a5e`). Free demo path with `?demo=1` (3,000/day shared quota). HMAC-signed mode for per-key quotas. ([Docs](https://asset-forge-hire.vercel.app/api-docs) | [GitHub](https://github.com/razel369/asset-forge-bundle)) - [Tollbooth](https://agenttoll.dev) - 37 paid x402 MCP tools: OSINT feeds (SEC 8-K, FRED, GDELT, flights, quakes, air quality, GitHub trending, HN), prediction market scans (Polymarket, Kalshi cross-platform arbitrage), web intel (scrape, stack detection, lead scoring), and agent security (threat intel, supply chain IOCs). $0.01–$0.10 USDC on Base. No account required. ([agent.json](https://agenttoll.dev/.well-known/agent.json) | [x402](https://agenttoll.dev/.well-known/x402) | [OpenAPI](https://agenttoll.dev/openapi.json)) - [GoldBean API](https://goldbean-api.xyz) — 146+ AI endpoints including Baidu OCR, Translation, TTS, LLM Chat with x402 micropayments on Base. From ### Production Success Metrics.01/call for premium AI. MCP server at [mcpize.com/mcp/goldbean](https://mcpize.com/mcp/goldbean). ([GitHub](https://github.com/wuzenghai616-lang/goldbean)) - [Signal Oracle](https://oracles-production.up.railway.app) - 360 agent-payable change-intelligence feeds on Base: DepWatch (breaking-change verdicts for any npm/PyPI/Maven/crates/RubyGems package), RegWatch (55 regulatory verticals — data privacy, AI governance, securities, tariffs, PFAS, and more), TariffWatch (US import-duty changes + combined §301/§232/IEEPA effective rates), CVEWatch/KEVWatch (new and actively-exploited vulnerabilities), SanctionsWatch (OFAC SDN), SEC EDGAR event watches (M&A, bankruptcy, going-concern, cyber incidents), Treasury/macro indicators, plus premium one-call verdict endpoints (DepAudit, PackageHealth, TariffAudit, ComplianceAudit, VendorRisk). $0.01–$1.00 USDC per call, free samples, machine-readable JSON. ([Discovery](https://oracles-production.up.railway.app/.well-known/x402) | [MCP](https://oracles-production.up.railway.app/mcp)) - [Tollbooth](https://x402toll.com) - 56 verified financial, tax & legal calculators for AI agents (net-pay, federal/state income tax, self-employment & estimated tax, capital-gains, LLC & entity comparison, mortgage/loan/refinance, retirement/RMD/Social-Security, HSA/FSA, crypto/DeFi, sales tax, plus $1 bundled tax-estimate reports). Every answer ships its 2026 primary source (IRS/SSA), a formula trace, and a reproducible SHA-256 hash — plus a free golden-vector self-check (`/v1/golden/:id`) so an agent can re-verify the math without trusting the server. $0.02–$1.00 USDC on Base mainnet (x402 v2 + CDP Bazaar discovery). No API keys, no signup. MCP: `npx tollbooth-x402`. ([OpenAPI](https://x402toll.com/v1/openapi.json) | [Catalog](https://x402toll.com/v1/catalog) | [Agent Card](https://x402toll.com/.well-known/agent-card.json) | [llms.txt](https://x402toll.com/llms.txt) | [Verify](https://x402toll.com/v1/golden/paycheck) | [npm](https://www.npmjs.com/package/tollbooth-x402)) - [MIDAX402](https://midax402.com) - Pay-per-query semantic search over 300+ curated x402 ecosystem entries: protocol mechanics, facilitators, ERC-8004, and MCP/A2A integrations. Four tiers from $0.03 to $0.25 in USDC on Base Mainnet via the CDP Facilitator, no signup or API key required. ([OpenAPI](https://midax402.com/openapi.json) | [Agent Card](https://midax402.com/.well-known/agent-card.json)) - [Yield.xyz AgentKit](https://mcp.yield.xyz/mcp) - MCP server for DeFi yield discovery & execution across 80+ networks (staking, lending, vaults, RWAs); 2,988+ opportunities. Free discovery tier; paid tools (wallet balances, unsigned enter/exit/manage tx building) at $0.001 USDC per call on Base. No signup — agents pay via x402. ([Discovery](https://mcp.yield.xyz/.well-known/x402)) - [ToolSnap MCP](https://mcp.toolsnap.app) — 28 context-efficient MCP tools for AI agents: web extraction, data processing, SEO, image processing. Flagship `fetch_extract` benchmarked at 98.1% token reduction (53,820 → 2,001 tokens, saving ~$0.156/call at Sonnet pricing). x402 v2 on Base with EIP-3009 `transferWithAuthorization`. Dual payment: pay-per-call $0.02 USDC or prepaid ($0.50 deposit → $0.01/call off-chain, no per-call gas, no 402 round-trip). 27 tools free, no API keys. Cloudflare Workers edge-native, 0ms cold start. Glama A rated. ([GitHub](https://github.com/icosaedro-git/toolsnap-mcp) | [Glama](https://glama.ai/mcp/connectors/app.toolsnap/toolsnap-mcp)) - [Veles Finance Agent](https://veles-finance-gateway.fly.dev) - Production FastAPI + LangGraph financial analysis service with x402 paywall on Base. Provides SEC 10-K extraction, stock due diligence, and Kelly Criterion at $0.01-$0.05 USDC per request. ([Discovery](https://veles-finance-gateway.fly.dev/.well-known/x402)) - [Denpyo — Japan Invoice & Receipt Reader](https://denpyo-api.hp-vladic.workers.dev) - OCR Japanese invoices (請求書) and receipts (領収書) into structured JSON — vendor, line items, 8%/10% consumption-tax breakdown — with the qualified-invoice registration number (T+13 digits) verified against Japan's National Tax Agency registry in the same call. $0.01-$0.04 USDC on Base & Solana. Failed analyses are not charged. MCP: `npx -y denpyo-mcp`. ([OpenAPI](https://denpyo-api.hp-vladic.workers.dev/openapi.json) | [llms.txt](https://denpyo-api.hp-vladic.workers.dev/llms.txt) | [GitHub](https://github.com/vladic-corp/denpyo-api)) - [BridgeNode](https://bridgenode.cc) - DeepSeek V4 Flash v2 inference via x402 on Solana. No registration, no API keys. Per-call pricing at $0.001 USDC via prepaid deposit. MCP-compatible. ([Discovery](https://bridgenode.cc/.well-known/x402) | [OpenAPI](https://bridgenode.cc/openapi.json)) - [Appraxa IP Valuation](https://api.appraxa.com/v1/info) - Standards-based patent valuation (DIN 77100 relief-from-royalty), calibrated on professional valuation cases. From $0.99 per valuation, USDC on Base. - [Venture NL Open-Data](https://api.pogo-tb.nl) - Dutch government open-data API for AI agents: RDW vehicle records (kenteken lookup), BAG addresses and postcode bulk lookup, reverse geocoding, vehicle brand search, and APK expiry alerts. Free previews on every route; $0.001-$0.005 USDC per call on Base. CC0/CC BY licensed sources with attribution in every response. ([OpenAPI](https://api.pogo-tb.nl/openapi.json) | [.well-known/x402](https://api.pogo-tb.nl/.well-known/x402) | [pricing](https://api.pogo-tb.nl/pricing)) - [mdapi](https://md.fastdb.in) - HTML-to-Markdown API for AI agents: POST a URL or raw HTML, get clean LLM-ready Markdown (Readability article extraction, tables preserved); POST /extract returns structured JSON (title, byline, links, images, meta). $0.005 USDC per call via x402 on Base, no signup, no API key. ([OpenAPI](https://md.fastdb.in/openapi.json)) - [chainpulse](https://md.fastdb.in/pulse/) - Real-time crypto market data API for AI agents: POST /price (aggregated USD spot prices with confidence score, incl. Base ERC-20s by address), POST /gas (live gas + USD transfer cost on Ethereum/Base/Arbitrum/Optimism/Polygon), POST /tvl (DeFi protocol TVL via DefiLlama slugs). $0.001 USDC per call via x402 on Base, no signup, no API key. ([OpenAPI](https://md.fastdb.in/pulse/openapi.json)) - [Lazaretto](https://lazaretto.dev) - Pre-install security verification for AI agent skills, tools, and npm packages. Free, no-key lockfile check: POST a `package-lock.json`, `yarn.lock`, or `pnpm-lock.yaml` and every pinned version is matched against published malicious-package advisories in one call, catching compromised releases like `chalk@5.6.1` and `@ledgerhq/connect-kit@1.1.6` while leaving their clean releases alone. Paid full scan adds deterministic behavioral analysis for credential theft, exfiltration, obfuscation, prompt injection, and install-time droppers, with file-and-line evidence and no LLM in the serving path; verdicts are SHA-256-bound so an agent can re-verify what landed on disk. $0.03 USDC on Base (x402) or prepaid bundles down to $0.016/scan. Remote MCP server (zero-install) plus `npx lazaretto-mcp` and a GitHub Action. ([OpenAPI](https://lazaretto.dev/openapi.json) | [Discovery](https://lazaretto.dev/.well-known/x402) | [Agent Card](https://lazaretto.dev/.well-known/agent-card.json) | [MCP](https://github.com/jamesdfinance-dev/lazaretto-mcp)) - [Utilia Solana Preflight](https://utilia.ink) - Deterministic Solana transaction simulation, confirmed-transaction diagnostics, priority-fee, and SPL token-risk APIs plus bounded PDF and audio transforms, payable in USDC through x402 v2 at $0.002-$0.01 per call. No signup or API key; hosted MCP settles on Solana and explicit HTTP aliases support Base. Includes OpenAPI, x402 discovery, and an on-chain Solana agent identity. ([Discovery](https://api.utilia.ink/.well-known/x402) | [MCP](https://api.utilia.ink/mcp) | [OpenAPI](https://api.utilia.ink/openapi.json) | [On-chain identity](https://8004market.io/agent/solana/mainnet-beta/1462)) - [SuVerse Pay](https://suverse-pay.suverse.io) - Payment gateway + API catalog with ~490 paid endpoints on one origin: crypto market data, Polymarket smart-money verdicts, token-safety forensics (Base + Solana), macro/gov datasets, and an x402 endpoint liveness probe. $0.05–$0.75 USDC per call, multi-chain settlement (Base + Solana + Cosmos Noble) via a self-hosted facilitator, no API keys or signup. ([OpenAPI](https://proxy.suverse.io/openapi.json) | [Catalog](https://suverse-pay.suverse.io/catalog) | [MCP](https://www.npmjs.com/package/@suverselabs/mcp-server) | [Buyer SDK](https://www.npmjs.com/package/@suverselabs/x402-client)) - [Studio X](https://www.studio-x.cc) - Production image and video generation API with 11 models, per-generation x402 pricing, and USDC settlement on Base. ([OpenAPI](https://www.studio-x.cc/openapi.json) | [x402 discovery](https://www.studio-x.cc/.well-known/x402)) ### Production Success Metrics **Key Performance Indicators:** - 10.5M+ transactions - AIsa cumulative network volume - 500K+ weekly transactions - Ecosystem-wide payment activity - $180M+ market cap - Combined ecosystem valuation - 2-second settlement - Average production payment finality - 10,000%+ growth - Year-over-year transaction volume increase ### Multi-Chain Production Support | Chain | Status | Facilitators | Settlement | Production Examples | | ------------- | ----------- | -------------------------- | --------------- | ------------------------- | | Base | Production | Coinbase CDP, Cloudflare | Instant (2s) | AIsa, Bitget, thirdweb | | Base Sepolia | Testnet | Coinbase CDP | Instant (2s) | Development, Testing | | Ethereum | Production | Cloudflare | Deferred | Enterprise DApps | | Solana | Production | Community | Instant (<1s) | High-frequency trading | | BNB Chain | Production | Pieverse | Instant (2s) | Gaming, NFTs | | Radius | Production | Community | Instant (<1s) | Micropayments | ### Data & Social APIs - [API Witchcraft (API_Dalla)](https://apiwitchcraft.duckdns.org) — 19 hands-off pay-per-call APIs for AI agents, settling USDC on Base via Coinbase CDP Facilitator. Covers compliance (VAT/VIES validation, e-invoicing mandates, OFAC/EU/UN/UK sanctions + PEP screening, US export-control ECCN, FX rates, EPR fees), geo (IP lookup + VPN/Tor detection), crypto (prices, trending, collective arbitrage), agent-security (AgentDojo scenarios + SPAR scoring), web (scrape-permit check, BJJ lineage), lifestyle (digital-nomad visa index, weather micro-betting), and x402 seller tooling (reconcile, balance). $0.002 USDC/call, no API keys, no signup. ([llms.txt](https://apiwitchcraft.duckdns.org/llms.txt) | [openapi.json](https://apiwitchcraft.duckdns.org/openapi.json) | [agent.json](https://apiwitchcraft.duckdns.org/.well-known/agent.json)) - [KR-DART Events](https://dartapi.ljaysk.com) - Real-time Korean corporate disclosure (DART) events for AI agents. Korea's ~2,500 daily filings polled every 15s, classified into 31 categories with importance scores, English labels and English company names. Cursor-delta stream, material-only screen, per-company timelines. $0.002-$0.01 USDC on Base or Solana via x402 (Coinbase CDP facilitator, Bazaar discovery on every 402). No API keys, no signup. ([llms.txt](https://dartapi.ljaysk.com/llms.txt)) ([OpenAPI](https://dartapi.ljaysk.com/openapi.json)) ([GitHub](https://github.com/LJaysk/kr-dart-events)) ([MCP](https://github.com/LJaysk/kr-dart-events/blob/main/mcp_server.py)) - [Tinstop Website Intelligence API](https://tinstop.com) - Pay-per-call domain security and performance audits on Base: DNS, SSL/TLS, HTTP security headers, SPF/DKIM/DMARC, and PageSpeed. $0.02–$0.10 USDC via x402 v2 (EIP-3009). ([OpenAPI](https://tinstop.com/openapi.json) | [Discovery](https://tinstop.com/.well-known/x402) | [llms.txt](https://tinstop.com/llms.txt)) - [x402-seller](https://x402-seller-m8nx.onrender.com) - Decision-ready crypto market + on-chain intelligence for AI agents. 13 keyless pay-per-call endpoints on Base mainnet (no account, no API key): verdict-first ANSWER endpoints — `/vet` (one-call token due-diligence → clear/caution/avoid), `/brief` (market regime → risk_on/off), `/screen` (batch rug-check up to 8 tokens, sorted safest-first) — plus rug/honeypot safety with green+red flags, perp funding/OI, DEX pools, new launches, prices, and stocks. $0.001–$0.03 USDC. Redundant keyless facilitators (no CDP key needed). ([OpenAPI](https://x402-seller-m8nx.onrender.com/openapi.json) | [Discovery](https://x402-seller-m8nx.onrender.com/.well-known/x402.json) | [llms.txt](https://x402-seller-m8nx.onrender.com/llms.txt) | [GitHub](https://github.com/wyattpalm2-eng/x402-seller)) - [Sirenic](https://api.sirenic.eu) - Official French & European company data for AI agents, from open government sources (INSEE/INPI, Etalab 2.0). Search 30M French companies, full profiles, KYB files with sanctions screening (5 official lists, scored matches), filed financials, BODACC legal alerts, sector benchmarks, failure-risk score, AI health summaries, PDF reports; European registers (BE/UK/NO/EE/LV) + worldwide GLEIF in one unified schema. $0.001–$0.50 USDC per call on Base mainnet via x402 v2 — no account, no API key; failed requests are never charged. MCP server with 25 tools. ([llms.txt](https://api.sirenic.eu/llms.txt)) ([OpenAPI](https://api.sirenic.eu/openapi.json)) ([MCP](https://api.sirenic.eu/mcp)) ([Examples](https://github.com/sirenic-eu/sirenic-examples)) - [Agent Utility API](https://agent-api-production-169b.up.railway.app) - 8 pay-per-call utility tools for AI agents in USDC on Base via x402 (CDP facilitator), served over both HTTP and MCP: company enrichment ($0.01), email verification ($0.01), Chainlink crypto/FX prices ($0.005), webpage-to-clean-text ($0.02), structured PDF extraction ($0.05), X/LinkedIn profile lookup ($0.05), Amazon/KDP market data ($0.05), and YouTube transcription ($0.10). Bazaar discovery extensions on all 402 responses; listed in the official MCP Registry. No API keys, no signup. ([Discovery](https://agent-api-production-169b.up.railway.app/.well-known/x402)) ([llms.txt](https://agent-api-production-169b.up.railway.app/llms.txt)) ([MCP](https://agent-api-production-169b.up.railway.app/mcp/mcp)) - [afriref / latamref / asiaref / euroref / usaref / ausref](https://afriref.dev) - Verified government reference data for 58 countries across six continent-scoped brands on one engine: central-bank policy rates, VAT, minimum wages, CPI inflation, corporate & personal income-tax brackets and public holidays — 406 series, every value cited to its official gazette, central-bank or statistics-office source with effective dates and staleness flags. Africa 22 (incl. all 7 WAEMU members on one reconciled BCEAO rate and all 6 CEMAC members on one reconciled BEAC TIAO), Latin America 16, Asia 10, Europe 6, North America 2, Australasia 2. Honest structural nulls where no figure exists rather than a fabricated one — the US has no federal VAT, Malaysia levies SST and not a VAT at all, Italy and Bangladesh have no national statutory minimum wage, Singapore runs an S$NEER band instead of a policy rate, Argentina abolished its policy rate. From $0.005 USDC per series call (x402 v2, CDP-facilitated on Base, Bazaar discovery); free catalog and public-holiday endpoints; HMAC-signed change-alert webhooks; computed answers (VAT breakdown, minimum-wage compliance, working days, income tax, gross-to-net payroll); and cross-border VAT determination for digital-services sellers (EU, UK, South Africa), each rule cited to the statute. No API keys, no signup. ([Discovery](https://afriref.dev/.well-known/x402.json)) ([llms.txt](https://afriref.dev/llms.txt)) - [ZARONIA Verify](https://api.zaroniacalculator.co.za) - Independent, audit-grade recomputation of South African ZARONIA-linked FRN and money-market coupons against the SARB Compounded ZARONIA Index: full workings, a verdict at 0.05bp tolerance, and provenance; reproduces BESA/bank acceptance values to 4dp. From $0.005 USDC (index point) to $0.25 (FRN coupon verification), x402 v2 on Base; free conventions and latest-index endpoints. ([Discovery](https://api.zaroniacalculator.co.za/.well-known/x402.json)) ([llms.txt](https://api.zaroniacalculator.co.za/llms.txt)) - [WebIntel](https://x402.omardev.xyz) - EU/NL-focused web & business intelligence for AI agents on Base. 10 pay-per-call endpoints ($0.005–$0.25): page-to-markdown, page metadata, sitemap discovery, tech-stack detection, DNS & email-provider intel, EU company enrichment with live VIES VAT validation + Dutch KvK/BTW, standalone EU VAT validator, domain registration/age (RDAP), a 0–100 B2B lead score, and a full domain dossier. USDC on Base via Coinbase CDP facilitator, Bazaar discovery on every 402, no API keys or signup. ([Catalog](https://x402.omardev.xyz/)) ([Discovery](https://x402.omardev.xyz/.well-known/x402.json)) ([OpenAPI](https://x402.omardev.xyz/openapi.json)) ([llms.txt](https://x402.omardev.xyz/llms.txt)) - [PARADIGMA Crypto Feed](https://opportunity-api-production.up.railway.app) - 26 pay-per-call crypto data endpoints for AI agents: scored airdrop/quest opportunities (Galxe), trending tokens, spot prices for 25 coins, top stablecoin yields, chain TVL rankings, Fear & Greed index. $0.005-$0.01 USDC per call on Base mainnet via CDP facilitator (x402 v2, Bazaar discovery extension). No API keys. - [base-token-intel](https://base-token-intel.onrender.com) - Pay-per-call Base L2 token intelligence for trading agents: newly created DEX pools (Uniswap v2/v3, Aerodrome) with liquidity, ERC-20 risk reports (owner/renounce, bytecode red flags), and deployer intelligence (deployer wallet age, tx count, throwaway-wallet flags — a rug-pull signal not in free APIs). $0.01–$0.03 USDC on Base via Coinbase CDP facilitator, no API keys, no signup. ([Discovery](https://base-token-intel.onrender.com/.well-known/x402) | [OpenAPI](https://base-token-intel.onrender.com/openapi.json)) - [Voda Astro Data API](https://astro.dutchdata.io) - Astrology full charts, transit/mundane aspect time series, and global location data for AI agents. Flat $0.50 per request, x402 v2 USDC on Base mainnet plus MPP (Stripe/Tempo) on the same routes. No API keys, no signup. ([OpenAPI](https://astro.dutchdata.io/openapi.json)) ([llms.txt](https://astro.dutchdata.io/llms.txt)) ([Agent Card](https://astro.dutchdata.io/.well-known/agent-card.json)) - [NIMATRON COT](https://api.nimatron.com/free/cot/catalog) - CFTC Commitment of Traders positioning across all 438 futures markets (disaggregated + TFF): trader-category breakdowns, week-over-week changes, 52-week COT index, crowding-extremes screener, spec-flow rankings, and sector views. Live previews in every 402 response. $0.05–$1.00 USDC per call on Base via CDP facilitator, no API keys. Updated every Friday within hours of CFTC release. ([Discovery](https://api.nimatron.com/.well-known/x402)) ([llms.txt](https://api.nimatron.com/llms.txt)) ([Catalog](https://api.nimatron.com/free/cot/catalog)) - [enrich-gate](https://enrich-gate.vercel.app) - Pay-per-call gateway for AI agents: Google web search ($0.01), Exa neural search ($0.012), Firecrawl URL→markdown scraping ($0.015), and LLM inference ($0.005). USDC on Base via the Coinbase CDP facilitator — no accounts, no API keys, no subscriptions. MCP server included so any MCP agent can use it with just a funded wallet. ([Catalog](https://enrich-gate.vercel.app/)) ([GitHub](https://github.com/enrichgateagent-png/x402-agents)) - [GAUGE — Verifiable Environmental Signals](https://aeml-x402.zeabur.app/) - Flood-risk & river-anomaly checks for AI agents on Base. Real-time US river water level (gage height), streamflow & flood stage vs official USGS/NOAA thresholds, plus 5-year seasonal statistical anomaly (percentile/strata) and record_hash + OpenTimestamps verifiable provenance. Also air quality (US AQI/PM2.5) and precipitation (rainfall/drought). Skill $0.05; add-ons $0.01–$0.03; region $0.10; census $1. Free raw + sample, no API key. x402 USDC on Base. ([agent.json](https://aeml-x402.zeabur.app/.well-known/agent.json) | [llms.txt](https://aeml-x402.zeabur.app/llms.txt) | [Sample](https://aeml-x402.zeabur.app/gauge/sample)) - [SNTL — Helium Intelligence](https://a2a.sntl.site) - Live x402 agent for real-time Helium/Solana DePIN threat classification, anomaly scoring, wallet intelligence & forensic event chains over a 600K+ event datalake. 26 pay-per-call skills at $0.01 USDC (Solana mainnet, gasless via PayAI), first tier free, no signup. Agent-card: https://a2a.sntl.site/.well-known/agent-card.json · Source: github.com/substreambc/my-agent - [x402-endpoints](https://x402-endpoints.onrender.com) - 40 pay-per-call x402 endpoints for AI agents on Base/USDC: official EU/global registries (GLEIF LEI, VIES VAT, UK Companies House, INSEE Sirene, EUR-Lex, ECB, BODACC, CVE, openFDA), crypto pre-trade safety (Solana rug/honeypot checks, perp funding/OI radar, DEX-CEX spread), and agent decision endpoints — due-diligence dossiers, structured analysis reports, action preflight clearance with a signed Ed25519 ClearancePacket, output QA + rewrite, prompt-injection/content-security scans, OFAC wallet screening, and x402 seller-trust. Every decision endpoint returns a structured machine-readable verdict + an offline-verifiable signed receipt. $0.005–$0.50 USDC via the Coinbase CDP facilitator, no API keys, no signup. ([Discovery](https://x402-endpoints.onrender.com/.well-known/x402.json) | [Agent Card](https://x402-endpoints.onrender.com/.well-known/agent-card.json) | [llms.txt](https://x402-endpoints.onrender.com/llms.txt) | [MCP](https://x402-endpoints.onrender.com/mcp) | [GitHub](https://github.com/digitalweb33333-creator/x402-endpoints)) - [botsmith](https://x402.botsmith.dev) - Pay-per-call web and on-chain intelligence for AI agents, no API keys. `read` (any URL to clean, boilerplate-free markdown, $0.003), `dossier` (full domain intelligence in one call: DNS, SPF/DMARC, RDAP registration, live TLS cert, $0.004), and `onchain` (EVM address due-diligence: contract-or-wallet, scam and reputation flags, balances, verification, deployer, on Base/Ethereum/Optimism, $0.004). USDC on Base via the Coinbase CDP facilitator, x402 v2 with Bazaar discovery. ([Discovery](https://x402.botsmith.dev/.well-known/x402) | [Catalog](https://x402.botsmith.dev/catalog) | [MCP](https://www.npmjs.com/package/botsmith-mcp)) - [TerraDeed Scrape API](https://api.terradeed.co.uk) - Pay-per-use web scraping and structured JSON extraction. $0.01/$0.05 USDC on Base mainnet. LLM-ready markdown, JS rendering, schema-driven extraction. ([GitHub](https://github.com/terradeed/terradeed-scraper)) - [EZ-Path](https://ezpath.myezverse.xyz) — Best-execution pay-per-request DEX meta-router. Races 10+ venues (0x, ParaSwap, Aerodrome, Uniswap V3, Curve, Balancer, 1Inch, CoW Swap, Synthetix) concurrently on Base mainnet. Three tiers: basic ($0.03, 0x only), resilient ($0.10, dual-lane race), institutional ($0.50, all venues). Strict agent wallet drain protections with hardcoded toll address validation. x402 v2 USDC on Base. Supports ElizaOS plugin integration. ([Discovery](https://ezpath.myezverse.xyz/.well-known/agent.json)) ([npm](https://www.npmjs.com/package/plugin-ezpath)) ([GitHub](https://github.com/infiniteezverse/ez-agentic-price-path)) - [Sentinel Intelligence API](https://sentinel-intelligence-api.onrender.com) - Pay-per-brief fintech and AI governance intelligence. BNPL/embedded finance and AI compliance research briefs at $2 USDC; on-demand research on any topic at $10 USDC. CDP-facilitated settlement on Base mainnet. ([Discovery](https://sentinel-intelligence-api.onrender.com/.well-known/x402.json)) ([GitHub](https://github.com/ucsandman/sentinel-api)) - [x402deploy](https://x402deploy.vercel.app) - Two pay-per-call tools for AI agents on Base mainnet: `web_search` ($0.005, organic web results as JSON) and `read_url` ($0.005, fetches a page → cleaned main text). Keyless USDC settlement via the xpay facilitator — no API key, no accounts, no CDP. MCP server: `npx -y github:minhthai1995/x402-search-mcp`. ([MCP](https://github.com/minhthai1995/x402-search-mcp)) ([serp](https://x402deploy.vercel.app/api/serp)) ([read](https://x402deploy.vercel.app/api/read)) - [CrowdPull public-data API](https://crowdpull.click) - Capped public-data jobs for AI agents: marketplace leads, rental comps, product reviews, hiring signals, and row enrichment. USDC on Base via x402 with no separate account or API key. ([OpenAPI](https://crowdpull.click/openapi.json) | [Discovery](https://crowdpull.click/.well-known/x402) | [Directory](https://crowdpull.click/api/directory) | [MCP](https://crowdpull.click/mcp)) - [Groundcheck](https://groundcheck.seiche.info) - Claim grounding and delivery attestation for AI agents: machine-verified verdicts (supported/refuted/unverified) with confidence scores and cited sources, grounded against live web sources. Signed offline-verifiable receipts bind an x402 payment to what was actually delivered. Free single-claim tier; paid endpoints $0.005-$0.05 USDC on Base via the Coinbase CDP facilitator, x402 v1+v2 with Bazaar discovery on every 402. No API keys, no signup. ([Discovery](https://groundcheck.seiche.info/.well-known/x402.json)) ([OpenAPI](https://groundcheck.seiche.info/openapi.json)) ([MCP on npm](https://www.npmjs.com/package/groundcheck-mcp)) ([GitHub](https://github.com/beepboop2025/groundcheck)) - [OSF — Open Source Filings](https://osf-master-server.com) - Provenance-stamped public-domain US government and scientific data for AI agents. SEC EDGAR, FRED, NOAA, openFDA, USGS, Crossref, and more — every record ships with a provenance URL back to its authoritative primary source. Pay-per-record x402 USDC on Base, $0.05–$0.50. Paid MCP server + listed in the official MCP Registry. No API keys, no subscriptions. ([MCP](https://api.osf-master-server.com/mcp) | [MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=osf-data-marketplace) | [Bazaar health](https://api.osf-master-server.com/x402/bazaar_health)) - [Touchstone](https://touchstone.locomot.io) - A deterministic-truth suite for AI agents: 14 pay-per-call endpoints whose answers reproduce a named public authority byte-for-byte, so an agent can re-run and verify an answer instead of trusting the seller. **Physical truth** — `/sky` (Sun/Moon/planet alt-az, rise/set/transit, twilight, phase; JPL DE421, ~1 arcsec) and `/field` (magnetic declination/inclination/intensity + secular variation; NOAA WMM2025, 100/100 on NOAA's published test values). **Time** — `/time` (IANA tzdata) and `/prosody` (CMUdict syllables/stress/meter). **Trust primitives** — `/timestamp`, `/sealed` (timelock encrypt-to-the-future), `/random/proof` (drand-backed provably-fair draws), `/verify/sig` (ecrecover, EIP-191/712). **Text & code workbench** — `/unit` (NIST SP 811 factors), `/readability`, `/syntax`, `/proofread`, `/cite` (APA/MLA/Chicago/BibTeX), `/diff`. Every answer is signed; same input → same bytes. USDC on Base via Coinbase CDP facilitator; x402 v2 with Bazaar discovery on every 402. No API keys, no signup; free schemas + samples at `/` and each `/<route>/example`. Prices $0.001–$0.003. ([free library on PyPI](https://pypi.org/project/almanac-compute/)) ([GitHub](https://github.com/savecharlie/almanac)) - - [AI Growth](https://kjtirbnxxymeumycrhqv.supabase.co/functions/v1/x402-seller?discover=1) - Real-data feeds for AI agents, settling via Coinbase CDP Facilitator on Base mainnet. Three pay-per-call products with x402 v2 Bazaar discovery: `opportunities` ($0.01, Claude-scored AI revenue opportunities from real GitHub bounties), `verification` ($0.02, timestamped proof-of-execution receipts — HTTP status, latency, phantom/simulation detection so agents can confirm an A2A service is real before paying), and `benchmarks` ($0.02, real endpoint liveness & latency measurements for routing). All data sourced from verified live calls — no synthetic data. No API keys, no signup. Select product via `?product=<id>`. ([Discovery](https://kjtirbnxxymeumycrhqv.supabase.co/functions/v1/x402-seller?discover=1)) - [MiroShark](https://github.com/aaronjmars/MiroShark) - Universal swarm-intelligence engine exposed as a paid API: POST a scenario to the `/x402/run` surface and hundreds of grounded LLM personas simulate Twitter, Reddit, and a prediction market hour-by-hour, returning an analytical report. USDC on Base via x402. ([GitHub](https://github.com/aaronjmars/MiroShark)) - [wrapper-agency APIs](https://fx.wrapper-agency.com) - Suite of 8 pay-per-call utility APIs settled in USDC on Base via x402 (free tier + one key for all): historical FX rates, color conversion, timezone/DST, fake/mock data, cron explainer, QR codes, data-format conversion, and encode/hash. ([FX](https://fx.wrapper-agency.com)) ([Color](https://color.wrapper-agency.com)) ([Timezone](https://tz.wrapper-agency.com)) ([Mock data](https://mock.wrapper-agency.com)) ([Cron](https://cron.wrapper-agency.com)) ([QR](https://qr.wrapper-agency.com)) ([Data format](https://data.wrapper-agency.com)) ([Encode](https://encode.wrapper-agency.com)) - [Crest x402 Data](https://data.crestsystems.ai) - x402 agent profiling plus crypto market data. Profile any x402 buyer or EVM wallet (whale score, behavior cluster, x402 spend graph, risk), plus prices, gas, DeFi, derivatives, NFTs, and DEX pairs. $0.002-$0.90 USDC on Base via Coinbase CDP facilitator, no API keys. ([Agent Card](https://data.crestsystems.ai/.well-known/agent.json) | [llms.txt](https://data.crestsystems.ai/llms.txt) | [l402-services](https://data.crestsystems.ai/.well-known/l402-services)) - [Pyrimid](https://pyrimid.ai) - Agent commerce protocol for x402-style USDC payments on Base. Includes on-chain vendor/product registry, payment router, affiliate attribution, MCP endpoint, and live catalog API for agent-discoverable paid services. Current mainnet proof: 3 vendors, 8 on-chain products, 4 routed test payments. ([Catalog](https://pyrimid.ai/api/v1/catalog)) ([MCP](https://pyrimid.ai/api/mcp)) ([Skill](https://pyrimid.ai/skill.md)) - **[Polybot Arb Intelligence](https://github.com/packrvnner/polybot-arb-api)** — Real-time cross-platform prediction market arb data (Polymarket+Kalshi+Myriad). x402 USDC on Base. [Live API](https://governments-ruth-distribution-breaks.trycloudflare.com/free/market-pulse) - [Bismuth](https://usebismuth.com) - Utility API suite for AI agents on x402. 7 pay-per-call services on Base mainnet, no API keys, no signup: `Bismuth Scraping` ($0.02 scrape / $0.10 BFS crawl — Playwright, SSRF-protected), `Bismuth Screenshot` ($0.01, Playwright PNG/JPEG), `Bismuth PDF Extraction` ($0.01, OCR + vision mode), `Bismuth Email` ($0.01, Resend + CC/BCC/attachments), `Bismuth Search` ($0.01, Tavily-ranked), `Bismuth Conversion` ($0.02 — image reformat, CSV→JSON, HTML→PDF, DOCX→PDF), `Bismuth Crypto Intelligence` ($0.01–$0.10, CoinGecko/DeFiLlama/CoinTelegraph/GitHub across 17 major coins). MCP server ships all tools under one npm install with automatic USDC micropayments. ([MCP Server](https://www.npmjs.com/package/x402-mcp-server) | [Scraping Discovery](https://x402-scraping-api-production.up.railway.app/.well-known/x402) | [Screenshot Discovery](https://usdc-screenshot-api-production.up.railway.app/.well-known/x402) | [PDF Discovery](https://pdf-api-production-cf1e.up.railway.app/.well-known/x402) | [Email Discovery](https://x402-email-api-production.up.railway.app/.well-known/x402) | [Search Discovery](https://x402-search-api-production.up.railway.app/.well-known/x402) | [Conversion Discovery](https://x402-conversion-api-production.up.railway.app/.well-known/x402) | [Crypto Discovery](https://crypto-sentiment-api-production-0ff4.up.railway.app/.well-known/x402)) - [Aigregator](https://x402.aigregator.com) - Structured data on 5,336+ AI tools via REST API and MCP server. Search, compare, and retrieve tool profiles. USDC micropayments on Base. ([MCP Server](https://x402.aigregator.com/mcp)) - [Xquik](https://xquik.com) - Real-time X (Twitter) data API with 7 MPP/x402 pay-per-use endpoints — tweet lookup, tweet search, user lookup, follower check, article extraction, media download, and trends. No accounts or subscriptions required. ([GitHub](https://github.com/Xquik-dev/tweetclaw)) ([npm](https://www.npmjs.com/package/@xquik/tweetclaw)) ([MCP Server](https://xquik.com/mcp)) - [AgentBodega](https://agentbodega.store) - Agent-ready paid API shelf with 51 x402-payable public-data, social-media, cloud/status, domain, artifact, launch-readiness, and x402-inspection endpoints. USDC on Base, no API keys or signup, full input/output contracts, examples, pricing, and payment metadata. ([Catalog](https://agentbodega.store/api/directory) | [OpenAPI](https://agentbodega.store/openapi.json) | [Discovery](https://agentbodega.store/.well-known/x402) | [MCP](https://www.npmjs.com/package/@agentbodega/mcp) | [GitHub](https://github.com/agentbodegastore/agentbodega)) - [glim.sh](https://glim.sh) - Live data from Twitter, Reddit, the web, GitHub, Amazon, and YouTube for AI agents. 11 MCP tools, $0.002-$0.015 USDC per call (Base/Solana/Monad). No API keys, no scraping stack. ([MCP Server](https://glim.sh/mcp)) ([OpenAPI](https://glim.sh/openapi.json)) ([GitHub](https://github.com/glim-sh/glim-mcp)) - [agentsvc.io](https://agentsvc.io) - 20 utility tools for AI agents via x402 USDC micropayments on Base. Tools: `ip-lookup`, `dns-lookup`, `qr-code`, `exchange-rates`, `email-validate`, `ssl-check`, `phone-validate`, `weather`, `translate`, `whois`, `crypto-prices`, `stock-prices`, `geocode`, `web-search`, `news-search`, `pdf-extract`, `screenshot`, `webpage-reader`, `html-to-pdf`, `ocr`. $0.001–$0.008 USDC per call. No API keys, no signup. Auto-discovery: [/.well-known/agent-services.json](https://agentsvc.io/.well-known/agent-services.json) | [Catalog](https://agentsvc.io/api/v1/services) | [OpenAPI](https://agentsvc.io/api/openapi.json) | [MCP Server](https://agentsvc.io/mcp-server.mjs) | ([GitHub](https://github.com/jakobautomation/agentsvc-mcp)) - [x402 Vending Machine](https://vending-machine-seven.vercel.app) - Base mainnet USDC **bundler hub** for AI agents (x402 V2 + Coinbase CDP): ~19 pay-per-call tools including multi-step packs (`bundle-infra`, `bundle-outbound`, `domain-intel`), DNS/TLS/WHOIS/HTTP utilities, email MX, FX, IP geo, CoinGecko spots, QR, page text extract, Base balances, and **Kronos** BTC/ETH candle research forecasts. Live data only; fail-closed (no settle on handler errors). CDP Bazaar indexed. ([Discovery](https://vending-machine-seven.vercel.app/.well-known/x402)) ([Agent catalog](https://vending-machine-seven.vercel.app/.well-known/agent-services.json)) ([OpenAPI](https://vending-machine-seven.vercel.app/api/openapi.json)) ([llms.txt](https://vending-machine-seven.vercel.app/llms.txt)) ([GitHub](https://github.com/noesisx8/x402)) - [AgentData API](https://agentdata-api.com) - Real-time crypto market data for AI agents. 16 pay-per-request endpoints on Base Mainnet: prices, funding rates, volatility, liquidation levels, DeFi yields, cross-exchange arbitrage, technical indicators (RSI/MACD/BB/ATR), support/resistance, sentiment, stablecoin health, and historical OHLCV. Self-hosted facilitator, no accounts required. Supports x402 v2 with Bazaar discovery extension. ([Discovery](https://agentdata-api.com/discovery)) ([OpenAPI](https://agentdata-api.com/openapi.json)) - [x402 Finance API](https://x402-paid-api.x402-finance.workers.dev) - Live crypto market data (BTC/ETH/SOL at **$0.002 USDC**) + Token Safety analysis (honeypot/liquidity/ownership at **$0.05 USDC**). Native x402 V2 on Base Mainnet with Coinbase CDP Facilitator. Includes discovery, llms.txt, and MCP tool definitions. ([llms.txt](https://x402-paid-api.x402-finance.workers.dev/llms.txt)) - [DripMetrics](https://dripmetrics.ai) - Crypto market microstructure and options metrics for AI agents: VPIN, Kyle's lambda, roll spread, order-flow imbalance, BTC options (GEX, expected move, variance risk premium), Polymarket, Hyperliquid, and on-chain activity, plus an AI-written BTC market summary. $0.05–$0.25 USDC per call on Base via the Coinbase CDP facilitator; x402 v2 with Bazaar discovery on every 402. No API keys, no signup. ([OpenAPI](https://api.dripmetrics.ai/openapi.json)) ([MCP Server](https://mcp.dripmetrics.ai/mcp)) ([GitHub](https://github.com/DripMetricsAI/dripmetrics-mcp)) - [Stakao Agent Allocation Analysis](https://api.stakao.com/agent) - Informational Bittensor allocation analysis API for AI agents, paid with x402 v2 USDC on Base. Supports walletless model portfolio snapshots, wallet-specific preflight flows, OpenAPI, read-only MCP, and llms.txt discovery. ([OpenAPI](https://api.stakao.com/agent/openapi.json) | [Docs](https://stakao.com/docs/ai-agents.md) | [llms.txt](https://stakao.com/llms.txt)) - [GPT55 x402 Wallet Safety and Merchant Readiness](https://gpt55.558686.xyz) - x402-paid agent gateway for AI buyers that need wallet signing safety, EIP-712/Permit2 risk decoding, EVM transaction risk decoding, approval-risk auditing, x402 prepay trust checks, merchant-readiness reports, and GPT55 chat on Base USDC. Prices start at $0.0001 for chat, $0.004 for prepay checks, and $0.01 for signing/approval checks. ([Discovery](https://gpt55.558686.xyz/.well-known/x402)) ([OpenAPI](https://gpt55.558686.xyz/openapi.json)) ([Wallet Safety Kit](https://gpt55.558686.xyz/x402/wallet-signing-risk-kit)) ([MCP Config](https://gpt55.558686.xyz/mcp/config)) - [Fly Labs Agentic Market](https://flylabs.fun/agents) - YouTube data APIs for AI agents, paid in USDC on Base. Two endpoints live: `POST /api/agents/transcribe` ($0.03) returns a stable v1.0 JSON payload with verbatim transcript, language, time-indexed paragraphs, creator chapters, and canonical metadata (captions when available, Whisper fallback otherwise, no LLM rewrites). `POST /api/agents/engagement` ($0.02) returns view/like/comment counts, derived ratios, a composite engagement score, channel info (subscribers included), and full video context (tags, categories, thumbnail, availability, live status). Transparent cache on every response (`cache.hit`, `cachedAt`, `ageSec`) — transcripts are permanent, engagement refreshes every 6 hours. Typed error codes, OpenAPI 3.1, no signup. ([OpenAPI 3.1](https://flylabs.fun/api/agents/openapi.json)) ([Manifest](https://flylabs.fun/api/agents)) - [NicheData KDP Intelligence](https://nichedata.dev) - Niche demand and competition intelligence for Kindle Direct Publishing authors. AI agents query keyword-level data including demand scores, competition intensity, BSR ranges, revenue estimates, and pricing analytics. $0.03 USDC per query on Base via CDP Facilitator. Free discovery endpoint lists all available niches. ([OpenAPI](https://nichedata.dev/openapi.json)) ([Docs](https://nichedata.dev/docs)) - [AIServices](https://api.aiservices.to) - 16-endpoint crypto and market intelligence API for AI agents. 11 free endpoints (prices, trending, global market cap, gas tracker, predictions, news, social sentiment, swap quotes) plus 4 paid endpoints via x402: search ($0.01), technical indicators ($0.02), DeFi yields ($0.02), and URL metadata ($0.01). USDC on Base via Coinbase CDP facilitator. Remote MCP server at `/mcp` (8 tools, SSE transport). No API keys for free endpoints, no signup. ([Discovery](https://api.aiservices.to/.well-known/x402)) ([MCP](https://api.aiservices.to/mcp)) ([GitHub](https://github.com/vbkotecha/aiservices-api)) - [Intelica](https://api.intelica.dev) - Competitive intelligence API for autonomous AI agents. Analyzes any URL or company description and returns structured JSON with market positioning, competitors, pain points, and executable Market Score. 10 context modes including `regulatory_compliance`, `venture_screening`, `crypto_protocol`, and `sales_enablement`. Standard tier $0.05 USDC, Elite tier $1.00 USDC per call on Base and Solana mainnet. MCP server at `/mcp`. A2A protocol at `/message/send`. ([OpenAPI](https://api.intelica.dev/openapi.json)) ([Discovery](https://api.intelica.dev/.well-known/x402)) - [PulseNetwork](https://pulsenetwork.theaslangroupllc.com) - 75 pay-per-call intelligence APIs (930+ endpoints) for AI agents under one federated catalog: token-safety verdicts across 8 chains including Robinhood Chain (memecoin + EVM rug/honeypot analysis), macro & FRED-grade economic primitives, geopolitical risk, clinical-trials intel, US government spending, stablecoin/RWA monitors, sports data, prediction markets, immigration/tax/legal doc-prep, and more. $0.001–$2.00 per call — USDC on Base + Solana, native USDG on Robinhood Chain (eip155:4663). CDP-facilitated settlement, per-repo `/.well-known/x402.json` discovery on all 70+ hosts, no API keys or signup. ([Hub & catalog](https://pulsenetwork.theaslangroupllc.com)) ([llms.txt](https://pulsenetwork.theaslangroupllc.com/llms.txt)) ([OpenAPI](https://pulsenetwork.theaslangroupllc.com/openapi.json)) ([MCP](https://pulsenetwork.theaslangroupllc.com/mcp)) - [DevDrops](https://devdrops.run) - 22 pay-per-query data APIs for AI agents — prediction markets (Polymarket + Manifold), property intelligence, sports odds, regulatory filings, FX rates, weather, IP geolocation, academic papers, document summarisation (Claude), and more. $0.001–$0.10 USDC per query on Base. No API keys or subscriptions. ([OpenAPI](https://api.devdrops.run/openapi.json)) ([Catalog](https://api.devdrops.run/catalog)) - [Verification Oracle](https://agent-business.142.93.127.153.sslip.io) - Independent verification of agent work products — citation-support checks and data/schema validation returning wallet-signed attestations (EIP-191) — plus cited coding research that ships pre-verified with a signed attestation. $0.10/research call, $0.25/verification, USDC on Base mainnet via CDP facilitator. Free per-wallet quotas, free receipt-verification endpoint, Bazaar discovery extension, no API keys or signup. ([llms.txt](https://agent-business.142.93.127.153.sslip.io/llms.txt)) ([OpenAPI](https://agent-business.142.93.127.153.sslip.io/openapi.json)) ([Discovery](https://agent-business.142.93.127.153.sslip.io/.well-known/x402)) - [Regression Incoming — NFL Fantasy Rankings](https://api.regressionincoming.fyi) - Model-driven 2026 NFL preseason fantasy football rankings for AI agents. 5 x402-protected endpoints on Base mainnet: `GET /v1/rankings/preseason` ($1.00, full 412-player preseason rankings with confidence scores), `GET /v1/rankings/preseason/{player_id}` ($0.10, single-player projection by player ID), `GET /v1/draft-board/half-ppr` ($1.00, 320-player VOR draft board with floor/ceiling/tier), `GET /v1/draft-board/half-ppr/{player_id}` ($0.10, single-player draft board row), `POST /v1/bundle/purchase` ($3.00, 7-day unlimited-access JWT). USDC on Base via CDP Facilitator. Bazaar discovery extension on all 402 responses. No API keys or signup. ([Discovery](https://api.regressionincoming.fyi/.well-known/x402.json)) ([Catalog](https://api.regressionincoming.fyi/v1/bazaar)) - [Darrylbots x402 Research](https://tryponcho.com/m/darrylbots.com) - Agent-readable paid JSON research endpoints on Base USDC: stock-screen reports plus Polymarket/trading-agent analysis with structured rankings, risks, provenance, and disclaimers. $0.001 USDC per resource, no API key or account. ([Catalog](https://darrylbots.com/x402.json)) ([x402scan](https://www.x402scan.com/server/35285845-c871-4694-847b-c9b727cb474f)) - [agentdata-nl](https://agentdata-api.sander-van-aard.workers.dev) - European company screening for AI agents, straight from official public registers: company registers (UK, FR, NO, CH, CZ, FI, PL), insolvency checks (NL, FR), EU + UN sanctions screening, EU VAT (VIES), LEI, MiCA crypto-firm and token-registry checks, EURC peg monitoring and an x402 counterparty pre-payment trust check. 18 endpoints, $0.002–$0.18 per call, all-or-nothing billing — you are only charged when the task fully completed. x402 v2 with Bazaar discovery extension, USDC on Base via CDP facilitator. No API keys, no signup. ([x402 manifest](https://agentdata-api.sander-van-aard.workers.dev/.well-known/x402.json)) ([OpenAPI](https://agentdata-api.sander-van-aard.workers.dev/openapi.json)) ([llms.txt](https://agentdata-api.sander-van-aard.workers.dev/llms.txt)) ([MCP](https://agentdata-api.sander-van-aard.workers.dev/mcp)) ([GitHub](https://github.com/DarthSander/data_agent)) - [WebberSites x402 Data API](https://x402.webbersites.com) - 41 pay-per-call endpoints for AI agents, all $0.001–$0.009 USDC on Base via CDP facilitator: web scraping, document extraction (PDF/DOCX/CSV), single-page and whole-site SEO/accessibility audits, brand-kit/logo/icon/social-card generation, multi-page website building, DNS & email intelligence, geolocation, crypto data, a free machine message board, and a wallet-owned persistent Agent Datastore — give your agent a memory. Free 402 previews on page-check endpoints. No API keys, no signup. ([Discovery](https://api.webbersites.com/.well-known/x402)) ([OpenAPI](https://api.webbersites.com/openapi.json)) ([MCP Server](https://api.webbersites.com/mcp)) ([npm](https://www.npmjs.com/package/webbersites-x402-mcp)) ([GitHub](https://github.com/webberdesign/api.webbersites.com)) - [StillOS Notary](https://nolawealthfinancial.com/notary) - Signed, fail-closed trust & verification primitives for agent-to-agent commerce. `agent-clearance` is the counterparty credit-check before one agent pays another: OFAC SDN + live on-chain wallet screen → CLEAR/REVIEW/BLOCK. Plus `claim-verdict` (grade any claim vs external ground truth), `grade-strategy` (REAL_EDGE/REGIME_LUCK/NEGATIVE_EV), `screen-entity` (OFAC SDN), `insider-conviction`/`smart-money` (proprietary EDGAR scoring), and `distress-score` (single-ticker distress vs a backtested modified-Altman-Z model). Every response Ed25519-signed and independently verifiable, no account. Free tiers, then $0.02–$0.75 x402 USDC on Base via a self-hosted facilitator (no CDP dependency). Paid MCP server (edge-gate) listed in the official MCP Registry. ([llms.txt](https://nolawealthfinancial.com/llms.txt)) ([agent.json](https://nolawealthfinancial.com/.well-known/agent.json)) ([OpenAPI](https://nolawealthfinancial.com/openapi.json)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=stillos-edge-gate)) - [Anicca Compute Primitives](https://aniccanomac-mini-1.tail7a0ba4.ts.net) - 31 pay-per-call tools for AI agents spanning financial calculators, trading and risk signals, data utilities, and web research, plus [Franklin1's autonomous v2 storefront](https://franklin1.tail7a0ba4.ts.net) and three wallet-isolated `POST /image` storefronts that generate 1024×1024 images for $0.05. $0.001–$0.05 USDC on Base via x402, with no API keys or signup; the open-source Anicca earn framework routes revenue directly to each serving agent's own wallet. ([Anicca discovery](https://aniccanomac-mini-1.tail7a0ba4.ts.net/.well-known/x402.json)) ([Franklin1 image](https://www.x402scan.com/server/7e8ebdc1-7c3d-419f-b76b-e41bab7bb86c)) ([Franklin2 image](https://www.x402scan.com/server/af9283bc-b1f8-4e50-b474-abb1f5d082e0)) ([Claude-P image](https://www.x402scan.com/server/439753c7-81e9-4c3e-b383-3be9c7377d9e)) ([GitHub](https://github.com/Daisuke134/anicca)) - [Social Intel](https://socialintel.dev) — Instagram influencer search API for AI agents. Search by niche, country, demographics, or follower count → returns usernames, bios, follower counts, business categories, and public business emails. Single-profile lookup at $0.01; full search $0.50–$1.30 (100 leads). USDC on Base, Solana, Polygon, Arbitrum. No signup. ([OpenAPI](https://socialintel.dev/openapi.json)) ([MCP Server](https://socialintel.dev/mcp/)) ([Demo](https://socialintel.dev/v1/search?query=fitness&demo=true)) - [GlobalAPI](https://globalapi.dev) - Compliance and macro-economics API hub for AI agents across 43 endpoints. Crypto wallet sanctions screening checks any EVM, BTC, Solana, TRX, or XRP address against OFAC SDN, UK FCDO, and UN SC lists in <200ms ($0.002/check); unified DeFi counterparty check bundles sanctions + Tornado Cash labels + wallet age into a PASS/WARN/BLOCK verdict ($0.01). Economic indicators from official statistical agencies — BLS and FRED (US), ONS (UK), Eurostat (EU), Statistics Canada, ABS (AU), e-Stat (JP), IMF DataMapper (190 countries), World Bank (200 countries) — with AI commentary. Company registry lookups for Norway, Singapore, Ireland, France, Canada, and Denmark. No API key — x402 USDC on Base mainnet, $0.002–$0.10/call. ([OpenAPI](https://globalapi.dev/openapi.json) | [Discovery](https://globalapi.dev/.well-known/x402)) - [The Bot Wire](https://thebotwire.com) - Real-time news wire for AI agents: 40 curated sources (markets, crypto, tech, world, business, energy) refreshed every 5 minutes, full-text searched in ~1ms with per-article freshness timestamps. `GET /news` (ranked search with summaries) and `GET /headlines` (by category) at $0.005 USDC on Base via x402 v2; free preview tier, no API keys, no signup. ([Discovery](https://thebotwire.com/.well-known/x402) | [OpenAPI](https://thebotwire.com/openapi.json) | [llms.txt](https://thebotwire.com/llms.txt) | [MCP on npm](https://www.npmjs.com/package/botwire-mcp)) - [Sivut Public x402 Data APIs](https://pay.sivut.co) - Public page markdown conversion and x402 seller intelligence endpoints for AI agents, paid in USDC on Base via x402. Prices range from $0.003 to $1.00 per call; no signup or API key. ([OpenAPI](https://pay.sivut.co/openapi.json)) ([llms.txt](https://pay.sivut.co/llms.txt)) ([GitHub](https://github.com/rambov1/sivut-x402-public-data)) - [LoneStarOracle](https://lonestaroracle.xyz) - 39 x402-gated AI data services on Base: token forensics (TokenScope), smart contract audits (RattlerAI/CottonmouthAI/CopperheadAI), weather consensus, oil & gas (CrownBlock), on-chain intel (ChainScout), macroeconomics (MacroPulse), real estate, commodities, stablecoin risk, and more. $0.02-$2.00 USDC per call. No API keys. MCP server at mcp.lonestaroracle.xyz (38 tools, xyz.lonestaroracle/mcp-server v1.1.0). ([Discovery](https://token.lonestaroracle.xyz/.well-known/x402.json) | [MCP](https://mcp.lonestaroracle.xyz) | [Status](https://status.lonestaroracle.xyz)) - [TOUGH LOVE SECURITY ImageGen](https://toughlovesec.win/imagegen) - Pay-per-image AI generation powered by Cloudflare Workers AI (Stable Diffusion XL Lightning + Flux-1-Schnell). Three tiers: $0.50 single, $1.99 12-pack, $7.99 100-bundle. Stripe Checkout for humans, x402 for agents at $0.04/image. No accounts, no expiring credits. ([Launch post](https://toughlovesec.win/blog/launch-imagegen-stripe-x402)) - [QueryLines](https://querylines.com) - Surplus lines market data, per query. U.S. excess & surplus (E&S) insurance premium and policy-count statistics from state stamping office publications: time series, YoY summaries, and cross-state comparison by state, coverage line, and month/quarter/year. $0.10 single-state query, $0.50 cross-state compare, USDC on Base via CDP facilitator with Bazaar discovery. Free discovery endpoints, no API keys or signup; every response cites its source report. ([OpenAPI](https://api.querylines.com/openapi.json)) ([MCP Server](https://api.querylines.com/mcp)) ([llms.txt](https://querylines.com/llms.txt)) - [TOUGH LOVE SECURITY ClawWork](https://toughlovesec.win/work) - Instant AI labor marketplace with three tiers: $5 quick polish (90s turnaround), $25 deep brief (1.5K-3K word structured deliverable), $99 full deliverable (pitch decks, RFPs, content calendars). Stripe + x402 ($0.05/call on bulk). Powered by Claude 4.7 Sonnet. ([Launch post](https://toughlovesec.win/blog/launch-clawwork-ai-labor-marketplace)) - [TOUGH LOVE SECURITY Contract Risk Score](https://toughlovesec.win/api/contract-risk-score) - Smart contract risk scoring API for DeFi devs. Scores Ethereum / Base / Arbitrum / Optimism contracts across 10 risk categories (admin-key centralization, oracle exposure, honeypot indicators, known exploit signatures). $1.25 per 5-pack via Stripe, $0.25/call via x402. Triage layer between "free Etherscan glance" and "$50K formal audit." ([Launch post](https://toughlovesec.win/blog/launch-contract-risk-score-defi-security)) - [GLHFDD](https://199-119-137-189.nip.io) - AI-powered text analysis, code analysis, and data transformation APIs built by a self-hosted AI agent. Pay-per-call via x402 protocol on Base mainnet. `POST /analyze/text` ($0.01), `POST /analyze/code` ($0.02), `POST /transform/data` ($0.005). No API keys, no signup. Auto-discovery via [bazaar.json](https://199-119-137-189.nip.io/.well-known/x402-bazaar.json). - [Deepnets](https://api.deepnets.ai) - Solana token intelligence: safety analysis, deep wallet-funding-network mapping, holder breakdowns, social/Twitter research, trending feed, streamflow/staking lockup data. 13+ pay-per-request endpoints on Solana mainnet: `/api/token-safety/{mint}`, `/api/token-details/{mint}` (full holder + network breakdown), `/api/holder-analysis/{mint}`, `/api/social_research/{mint}`, `/api/wallet-details/{address}`, `/api/network-details/{networkAddress}`, `/api/trending`, `/api/watchlist`, `/api/flagged-tokens`, and more. $0.01 basic / $0.15 holder analysis. USDC on Solana, gas sponsored by the facilitator — no SOL needed. v2 with Bazaar discovery extension. ([OpenAPI](https://api.deepnets.ai/openapi.json)) ([Docs](https://api.deepnets.ai/docs)) ([Marketing](https://deepnets.ai/agents)) - [OnChain Token Safety (wick.pics)](https://onchain.wick.pics) - Multi-chain token-safety verdicts for AI agents: rug/honeypot verdict (0–100 + evidence), live sell-simulation, ownership/privilege checks, size-aware exit-safety, wallet drainer-approval + address-poisoning scans. One API covers PulseChain, Monad, Base & BSC — the free tools (GoPlus, Honeypot.is) don't cover PulseChain, and Monad safety coverage is rare anywhere. $0.01–$0.05 USDC per call on Base, self-hosted settlement. ([Discovery](https://onchain.wick.pics/.well-known/x402)) ([OpenAPI](https://onchain.wick.pics/openapi.json)) ([MCP on npm](https://www.npmjs.com/package/@wickpics/onchain-safety-mcp)) - [OpenPulsechain](https://safety.openpulsechain.com) - PulseChain blockchain analytics API with 28 x402-paid endpoints: token safety scores (0-100), opportunity signals, whale alerts, pair analytics (price impact, volatility), deployer reputation, AML funding tree, smart money feed, gas price, OHLCV history. Covers 5,900+ tokens. $0.001–$0.03 USDC per call on Base. ([x402 Discovery](https://safety.openpulsechain.com/.well-known/x402)) ([npm MCP](https://www.npmjs.com/package/@openpulsechain/mcp-server)) ([GitHub](https://github.com/openpulsechain/public)) - [DataFood (TOUGH LOVE SECURITY)](https://toughlovesec.win/agent-mesh) - Universal data hub for AI agents — 17 cross-niche sources (crypto prices, ETH gas, weather, news, HN, GitHub trending, DeFi yield, token risk via GoPlus, HHS healthcare-breach feed, geocoding, more) behind one `POST /api/data/bundle` call. **Bundle micropayments save up to 92% vs per-API alternatives.** Day pass $0.99 unlimited 24h, week pass $4.99. Payable via x402 USDC OR Stripe Checkout — same `session_id` works across every tool call. Free 1-row preview at `/api/data/preview?type=…&q=…`. ([Live demo](https://toughlovesec.win/agent-mesh)) ([MCP server](https://github.com/atmflow55/datafood-mcp)) ([x402 descriptor](https://toughlovesec.win/.well-known/x402.json)) ([catalog](https://toughlovesec.win/api/v1/catalog)) - [x402 Trust Oracle](https://x402oracle.com) - Pre-trade trust check for autonomous trading agents before paying market data, oracle, price signal, funding data, or execution-input endpoints. Endpoint https://api.x402oracle.com/v1/trade-check, route /v1/trade-check. Price: $0.002 / 2000 atomic USDC on Base mainnet eip155:8453. asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913. payTo 0x2DF1AEc598a104Fc15E80C0B60e50C497559A980. - [Askew](https://x402.askew.network) - Security and DeFi intelligence for AI agents. 5 pay-per-call endpoints on Base mainnet: `/yields` ($0.002, live APY across 5 chains via DefiLlama), `/staking/router` ($0.003, SOL/ATOM native vs liquid staking routing), `/research/query` ($0.003, search agent-economy research and experiment corpus), `/intel/threats` ($0.002, Guardian security threat summary), `/intel/feed` ($0.005, combined research + threats + staking strategic feed). Free preview at `/yields/preview` and `/health`. Self-hosted facilitator (xpay.sh). Auto-discovery: ([/.well-known/x402.json](https://x402.askew.network/.well-known/x402.json) | [llms.txt](https://x402.askew.network/llms.txt) | [/offers](https://x402.askew.network/offers)) - [BitBooth](https://app.heinrichstech.com/bazaar.json) - 6 utility, content, and security endpoints for AI agents on Base mainnet, settling via Coinbase CDP Facilitator. Tools: `echo` (x402 reference impl), `json-repair` (LLM tool-output cleanup with optional JSON Schema validation), `faker` (synthetic test data via @faker-js/faker), `render-pro` (full Playwright JS rendering + Mozilla Readability extraction for SPAs), `web-diff` (rendered URL change detection vs caller-supplied previous markdown), `approval-safety` (ERC-20 `approve(spender, amount)` pre-flight risk check — flags unlimited approvals to fresh contracts, EOA spenders, copycat tokens). $0.001 USDC per call for utility tier, $0.05 for premium tier. No API keys, no subscriptions. Self-hosted discovery at [bazaar.json](https://app.heinrichstech.com/bazaar.json). ([GitHub](https://github.com/Drock91/bitbooth-gateway)) - [EconDash](https://econdash.org) - Global macroeconomic data API for AI agents: 753 indicators across 298 countries (World Bank, FRED, OECD). 15 x402-protected endpoints for GDP, inflation, employment, trade, country profiles, rankings, and metadata. $0.02 USDC/call on Base. Also supports MPP (Tempo + Solana). ([Docs](https://econdash.org/docs/quick-start)) ([OpenAPI](https://econdash.org/m2m-openapi.json)) - [ShadowQuant Intelligence](https://sq-intel-x402.aries-lao.workers.dev) - Validated equities/options market research for AI agents: volatility regime (VIX term structure, cross-asset ratios), options IV, seasonal bias with FDR-adjusted significance, Granger lead-lag map, correlation regime, and market context. Every response embeds provenance — generation timestamp, honest staleness flag, methodology, and a publicly graded track record. $0.005-$0.02 USDC per call on Base. No API keys, no signup. Research data, not investment advice. ([Catalog](https://sq-intel-x402.aries-lao.workers.dev/)) ([Discovery](https://sq-intel-x402.aries-lao.workers.dev/.well-known/x402.json)) ([Terms](https://sq-intel-x402.aries-lao.workers.dev/terms)) - [anchor-x402](https://anchor-x402.com) - 16 x402-paid services for AI agents on Base + Solana mainnet. 9 commodity primitives (OFAC sanctions screen, bundled wallet intel, dual-chain hash anchoring, signed attestations, mainnet tx + calldata decode, ENS + Bonfida SNS resolve, USD prices, datetime parse), 1 async due-diligence investigator ($7.77, 5–10 min, signed markdown report + dual-chain anchor proof), 1 verifiable signed RNG (`/v1/roll`, drop-in VRF for game studios), and 5 universal LLM endpoints (roast, oracle with on-chain anchored verdict, tldr, aura, grade). Plus a hosted chatbot at [chat.anchor-x402.com](https://chat.anchor-x402.com) — connect with passkey or any browser wallet, pay only when you approve. MCP server: [`anchor-x402-mcp`](https://www.npmjs.com/package/anchor-x402-mcp). ([GitHub](https://github.com/hypeprinter007-stack/anchor-x402)) ([Discovery](https://anchor-x402.com/.well-known/x402.json)) ([Trust portal](https://anchor-x402.com/trust)) - [romefeller.app](https://romefeller.app) - Document intelligence API: scrub PII (email, CPF, CNPJ, phones, API keys), verify document completeness, assess risk, and extract structured fields from invoices, NF-e, contracts, and receipts. Regex + Claude AI hybrid. 4 paid endpoints at $0.005–$0.15 USDC per call on Base mainnet via Coinbase CDP facilitator. Free regex preview at `/preview` (no payment required). No API keys, no signup. ([/.well-known/x402.json](https://romefeller.app/.well-known/x402.json) | [OpenAPI](https://romefeller.app/openapi.json) | [llms.txt](https://romefeller.app/.well-known/llms.txt)) - [QuantOracle](https://api.quantoracle.dev) - 73 deterministic quant finance endpoints for AI agents: Black-Scholes pricing with full Greeks, Kelly Criterion, Monte Carlo simulation, Sharpe/Sortino/Calmar/VaR/CVaR risk metrics, Hurst exponent, GARCH, drawdown analysis, plus 10 paid composites (full risk audit, hedge recommendations, options strategy optimizer, portfolio rebalance plan). Math verified against 120 published-textbook accuracy benchmarks (Hull, Lopez de Prado, Kelly, Parkinson). $0.002–$0.10 USDC per call on Base + Solana mainnets via Coinbase CDP facilitator. Free tier: 1,000 calls/IP/day, no signup, no API key. 15 free interactive calculators backed by the same engine at quantoracle.dev. ([OpenAPI](https://api.quantoracle.dev/openapi.json) | [x402 Discovery](https://api.quantoracle.dev/.well-known/x402) | [AgentKit Integration](https://github.com/QuantOracledev/quantoracle/tree/main/integrations/agentkit) | [Calculators](https://quantoracle.dev) | [GitHub](https://github.com/QuantOracledev/quantoracle)) - [krewe](https://www.krewe.world) - Decentralized AI inference network on Base. Each `/v2/predict` call is fanned out to 3 independent miner nodes; 2-of-3 byte-equal consensus is required before the result settles. 4 pay-per-call endpoints: `text.structure` ($0.005, entity/email/date extraction), `text.embed` ($0.01, sentence embeddings), `web.scrape` ($0.02, fetch + clean URL payload), `text.complete` ($0.05, quantized SLM completion via Qwen2.5-0.5B-Instruct). Settlement via EIP-3009 `transferWithAuthorization`, gas paid by the orchestrator (~$0.001 on Base) and recovered from the payment. No API keys, no signup. Live consensus events stream at [/v2/live](https://www.krewe.world/dashboard) WebSocket. ([SDK](https://github.com/krewe-AI/krewe/tree/main/clients/x402-client)) ([Orchestrator](https://github.com/krewe-AI/krewe/tree/main/orchestrator)) ([Miner](https://github.com/krewe-AI/krewe/tree/main/miner)) - [x402 inference gateway](https://agent-production-1daa.up.railway.app) - OpenAI-compatible LLM chat completions for AI agents, paid per request in USDC on Base mainnet via the Coinbase CDP facilitator (Bazaar-indexed). x402 v2 `upto` scheme: authorize a ceiling derived from `max_tokens`, get billed actual token usage at upstream cost + 4% — from $0.001/call. 8 models (gpt-5.4-nano/mini, gpt-5.4, gpt-5.5, gpt-4o and gpt-4.1 families). No API key, no signup: point any OpenAI client at the URL. Billing transparency headers (`X-Billed-Usd`, `X-Quoted-Ceiling-Usd`) on every response; daily on-chain canary. Self-serve integration doc at [GET /](https://agent-production-1daa.up.railway.app/). ([GitHub](https://github.com/sebboseb/agent)) - [SolProbe](https://api.solprobe.xyz) - Solana token risk scanner for AI agents with four pay-per-request endpoints settling USDC on Base or Solana mainnet at the same price (gas sponsored by the CDP facilitator — no SOL or ETH needed). Rug check / A–F safety grade ($0.02), market signal ($0.20), full due-diligence with wash-trading and bundled-launch detection ($0.50), and a bring-your-own-wallet Jupiter swap executor ($0.15); x402 v2 with the Bazaar discovery extension, no keys or signup. ([llm.txt](https://api.solprobe.xyz/llm.txt)) ([OpenAPI](https://api.solprobe.xyz/openapi.json)) ([Discovery](https://api.solprobe.xyz/.well-known/x402)) ([agentic.market](https://agentic.market/services/api-solprobe-xyz)) - [SolSigs ProofGuard](https://solsigs.com/proofguard) - Post-payment trust and refund-evidence layer for AI agents using x402 endpoints. `/proofguard/evaluate` returns decision flags, receipt fields, trust scoring, and evidence links for Solana x402 calls. $0.003 USDC on Solana. ([GitHub](https://github.com/gra-kir/solsigs-proofguard)) ([x402scan](https://www.x402scan.com/server/e52b109e-420a-4e86-adf0-be7b5e12b302)) - [Usenami](https://agentic.market/services/api-usenami-io) - Multi-venue perp funding & RWA spread API for arb-aware AI agents. 6 pay-per-call endpoints on Base mainnet ($0.001–$0.010 USDC): per-venue funding rates across 30+ exchanges (`/v1/funding/current`, $0.001), cross-venue funding spread (`/v1/perp/funding-spread?ticker=BTC`, $0.001), oracle price-source family classification for basis-risk awareness (`/v1/perp/oracle-families`, $0.001), RWA perpetual coverage on Hyperliquid HIP-3 DEXes — stocks, metals, forex, commodities, pre-IPO synthetics (`/v1/rwa/perp-coverage`, $0.001), **historical funding for backtesting** (`/v1/funding/historical?ticker=&from=&to=&aggr=1h|4h|1d`, $0.005, 90d retention), and **sized-depth quotes** with precomputed slippage at $1K/$5K/$10K notional (`/v1/orderbook/depth/aggregate/{venue}/{symbol}?size_usd=N`, $0.010). Differentiated vs CoinGecko/CMC by perp-first focus + RWA inclusion + backtestable historical depth. x402 v2 with Bazaar discovery extension via Coinbase CDP Facilitator. MCP server with 6 paid + 2 free tools at [namixai/usenami-mcp](https://github.com/namixai/usenami-mcp). ([API base](https://api.usenami.io)) ([Provider](https://usenami.io)) - [melis.ai x402 Tools](https://agents.melis.ai) - 23 audit-verified pay-per-call utility endpoints for AI agents, settling in USDC on Base via Coinbase CDP Facilitator. Production fleet at `*.melis.ai`. Covers: web scraping ([ScrapePay](https://scrapepay.melis.ai/scrape) $0.01, Playwright + robots.txt-aware), HTML-to-markdown token reduction ([MarkdownOpt](https://markdownopt.melis.ai/markdown) $0.005), cached fetch ([CacheServe](https://cacheserve.melis.ai/fetch) $0.001), structured HTML extraction ([StructExtract](https://structextract.melis.ai/extract) $0.002), format conversion ([DocConvert-Text](https://docconvert-text.melis.ai/convert) $0.001, [DocConvert-PDF](https://docconvert-pdf.melis.ai/convert) $0.005), notifications ([NotifyRelay /email](https://notify.melis.ai/email) $0.005, [/notify (Telegram)](https://notify.melis.ai/notify) $0.002, [/webhook](https://notify.melis.ai/webhook) $0.001 HMAC-signed, SSRF-protected), JSON Schema validation ([SchemaGate](https://schemagate.melis.ai/validate-schema) $0.001), prompt-injection screening ([PromptGuard](https://promptguard.melis.ai/score) $0.002, [MemScrub](https://memscrub.melis.ai/scrub) $0.001), URL safety ([LinkRisk](https://linkrisk.melis.ai/profile) $0.005 lightweight, [LinkSafe](https://linksafe.melis.ai/verify) $0.01 Playwright+VirusTotal), embeddings + memory ([EmbedPay](https://embedpay.melis.ai/embed) $0.00005/1k tok, [MemoryServe /write](https://memoryserve.melis.ai/memory/write) $0.001, [/query](https://memoryserve.melis.ai/memory/query) $0.001), image moderation ([ImageGuard](https://imageguard.melis.ai/score) $0.002), wallet trust scoring ([KYA Oracle](https://kyaoracle.melis.ai/score) $0.005), response auditing ([xAudit](https://xaudit.melis.ai/validate) $0.002), multi-agent orchestration ([IntentFlow](https://intentflow.melis.ai/relay) $0.001, [LoopWall /issue](https://loopwall.melis.ai/issue) $0.001, [/hop](https://loopwall.melis.ai/hop) $0.0005). No API keys, no signup. ([MCP Server](https://www.npmjs.com/package/@melis-ai/x402-tools-mcp)) ([GitHub](https://github.com/mizukaizen/x402-tools-mcp)) ([Operator](https://melis.ai)) - [Base Capital](https://base-capital.vercel.app) - Autonomous x402 on-chain risk-intelligence API for AI trading agents on Base. Token risk scores and risk-ranked trending signals at $0.01 USDC/call, backed by an on-chain RiskStake reputation contract (ERC-8004 agent identity, optimistic dispute resolution with bonded challenges, builder-code attribution). No API keys, no accounts. ([manifest](https://base-capital.vercel.app/manifest)) ([openapi](https://base-capital.vercel.app/openapi.json)) - [x402agent.no](https://x402agent.no) - Norway's AI agent API gateway — 7 live services, 23 endpoints covering Norwegian company registers (500K+ companies from Brønnøysundregistrene), SEO backlinks with Domain Rating, weather forecasts (MET Norway), 3,785 statistical tables (SSB), property/address data (Kartverket), IP search (Patentstyret), and public transport (Entur). $0.005–$0.10 USDC per query on Base via Coinbase CDP facilitator. No API keys, no accounts. ([services.json](https://x402agent.no/services.json)) ([llms.txt](https://x402agent.no/llms.txt)) - [dotrockets Agent Tools](https://x402.dotrockets.com) - Multi-tool x402 hub for AI agents (5 endpoints, $0.02–$0.10 USDC on Base mainnet, x402 v1+v2, no API keys or signup, gas-sponsored): **cosmic** live geophysics (KP-index with G1–G5 storms, Schumann resonance from Tomsk State University since 1997, solar wind, X-ray flux), **ai-visibility** score 0–100 for any domain (AI-crawler access, llms.txt, schema.org, SSR, + live LLM brand-knowledge check) with recommendations, **screenshot** (full-page Chromium PNG), **scrape** → clean Markdown (Mozilla Readability, optional JS render), and **search** (Brave + DuckDuckGo fallback). Machine-readable catalog, MCP server, and /.well-known discovery; Bazaar extension schema on every endpoint. ([Catalog](https://x402.dotrockets.com/catalog)) ([MCP](https://x402.dotrockets.com/mcp)) ([.well-known/x402](https://x402.dotrockets.com/.well-known/x402)) ([llms.txt](https://x402.dotrockets.com/llms.txt)) - [GoCreative AI](https://api.gocreativeai.com) - 145+ pay-per-call APIs for AI agents across social enrichment, OSINT lookups, web scraping, image generation, and document intelligence. USDC on Base via x402 (also Stripe). Free 5 calls/day per IP demo tier (no signup). Native MCP server, official GitHub Action, 7 npm + 4 PyPI SDKs, 20 HuggingFace Spaces. $0.001–$0.10 USDC per call. ([MCP Server](https://api.gocreativeai.com/mcp)) ([OpenAPI](https://api.gocreativeai.com/openapi.json)) ([Discovery](https://api.gocreativeai.com/.well-known/x402)) - [fry.farm x402 Agentic Actions](https://fry.farm/x402/) - 15 pay-per-call USDC endpoints on Algorand mainnet: DeFi/DePIN data + non-custodial transaction builders (staking, LP farming, NFT mint, P2P). Unsigned atomic groups — agents sign with their own wallet. ([Catalog](https://fry.farm/x402/catalog) | [MCP](https://github.com/Fry-Foundation/fry-x402-mcp)) - [2s.io](https://2s.io) - Pay-per-call JSON API for AI agents. 35 endpoints: geo/IP, web extract + summarize + translate + screenshot, image compress + describe, barcodes (QR/Aztec/DataMatrix/PDF417), DNS + WHOIS, EVM gas oracle, US weather (NWS), climate stations + tides + sunrise (NOAA), live quakes + wildfires (USGS), Wikipedia, papers (arXiv/PubMed/Semantic Scholar), patents, federal court opinions + Federal Register + OFAC sanctions, US Census demographics, airport registry. Sub-cent to $0.03 USDC on Base via the Coinbase facilitator; bearer-account flow in preview. ([Discovery](https://2s.io/api/directory) | [OpenAPI](https://2s.io/openapi.json) | [.well-known/x402](https://2s.io/.well-known/x402) | [llms.txt](https://2s.io/llms.txt)) - [Seneschal](https://seneschal.space) - Monero & Zcash payment watching for AI agents: hand over a **view key** (read-only) and a webhook URL, get an HMAC-signed POST for every inbound XMR/ZEC payment — watches run on the operator's own full nodes, credit-metered at $0.02/day + $0.005/event, topped up via x402 USDC **or natively in XMR/ZEC**. Also: historical note scans, free Zcash UFVK derivation, live XMR/ZEC chain facts from $0.001, plus DeFi liquidation telemetry (Aave, Morpho, Spark, Compound at-risk borrowers) and Ethereum builder bid distributions. Settles via Coinbase CDP with Bazaar discovery on every route. REST + MCP, no API keys. ([Discovery](https://api.seneschal.space/.well-known/x402)) ([MCP Server](https://mcp.seneschal.space)) ([GitHub](https://github.com/Rotwang9000/seneschal-data-api)) - [x402 Entity-ID Resolver](https://entityresolver.xyz) - Canonical cross-registry entity-ID resolver for AI agents. One ambiguous company or crypto name/ticker ("Apple", "ETH", "Stripe") → ranked candidates with verified IDs fused across registries: SEC CIK + ticker, GLEIF LEI, Wikidata QID, CoinGecko slug, each tagged with the sources that agreed so every ID is checkable. The exact cross-registry lookup LLMs can't do reliably. $0.005 USDC per call on Base mainnet, gasless (EIP-3009), no API key. v2 with Bazaar discovery extension. ([OpenAPI](https://entityresolver.xyz/openapi.json)) ([llms.txt](https://entityresolver.xyz/llms.txt)) ([.well-known/x402](https://entityresolver.xyz/.well-known/x402)) - [HSH Data-on-Demand](https://dod.hshintelligence.com) - Made-to-order B2B data for AI agents on Base mainnet. Describe any data need in plain language, receive a custom quote, pay per call in USDC via x402. Live company intelligence (`hsh_company_intelligence` at $0.02/call, free `/v1/quote-smart` discovery). Built for arbitrary data fulfillment — lead lists, contact enrichment, custom pulls — quoted by scope ($1-$50). No signup, no API keys. Both HTTP API and MCP Streamable HTTP transports. ([Manifest](https://dod.hshintelligence.com/.well-known/agent-manifest.json)) ([Catalog](https://dod.hshintelligence.com/x402/catalog)) ([MCP](https://dod.hshintelligence.com/mcp)) ([GitHub](https://github.com/hshintelligence/data-on-demand)) - [img402](https://img402.dev) - Image hosting for AI agents. Upload an image, pay via x402, get a public CDN-backed URL. Three tiers: free (1MB, 7-day retention), $0.01 USDC (5MB, 1-year), $1 (5MB, permanent). USDC on Base and Solana via the Coinbase CDP facilitator; indexed in the CDP Bazaar. No API keys, no signup. Claude/agent skills available. ([Docs](https://img402.dev/docs) | [OpenAPI](https://img402.dev/openapi.json) | [llms.txt](https://img402.dev/llms.txt) | [Skills](https://github.com/img402/skills)) - [Melvea](https://api.melvea.com) — Citation-backed honey intelligence: structured varietal data and verifiable research provenance for 150+ honey varieties, including the obscure long tail foundation models get wrong. Every compositional datum resolvable to a real, published source (DOI/PMID). Endpoints: variety catalog, per-variety research citations, and grounded flavor/use recommendations — $0.02–$0.10 USDC per call on Base. ([llms.txt](https://api.melvea.com/llms.txt)) ([ai-plugin.json](https://api.melvea.com/.well-known/ai-plugin.json)) - [n0brains](https://n0brains.com) - Crypto intelligence with a live, auditable per-signal-type win-rate at [/proof](https://n0brains.com/proof) (forward returns vs BTC, 95% CI; underperforming types demoted in the open). 6 pay-per-call x402 endpoints on Base, $0.005/signal USDC, no account: signals, rotation, correlation, DEX liquidation map, S/R levels, macro. Also hosted MCP (23 tools) and `pip install n0brains-cli`. ([Discovery](https://api.n0brains.com/.well-known/x402.json)) - [Qonoro Intelligence API](https://api.qonoro.ai/docs) - x402-native intelligence APIs for AI agents and business workflows on Base mainnet. Endpoints include `/v1/company/research` for company intelligence, `/v1/competitors/analyze` for business competitor analysis, and `/v1/sales-signals/find` for sales signal detection. Structured JSON outputs include source-backed evidence and confidence scores. Pricing by endpoint via `/v1/pricing/{agent_id}`; additional services are documented in the API docs. - [Stelar Digital x402 API (Algorand)](https://api-algo.stelardigital.com) - Pay-per-call market data and grid-trading params for AI agents, on Algorand mainnet via the GoPlausible facilitator. 3 endpoints: live P&L telemetry, price/signal check, and grid-parameter recommendation. $0.005-$0.05 USDC per call. ([Discovery](https://api-algo.stelardigital.com/.well-known/x402)) ([Catalog](https://api-algo.stelardigital.com/catalog)) - [TrustBoost PII Sanitizer](https://api.trustboost.dev) — Context-aware PII sanitization for autonomous AI agent pipelines. Redacts emails, phone numbers, national IDs (RFC/CPF/CUIT/RRN), private keys, and financial data before text reaches LLMs. Every paid sanitization anchored on Solana via Helius — verifiable by any agent at `/verify/{anchor_tx}`. 8 languages: EN, ES-LATAM, PT-BR, DE, JA, FR, IT, KO. Privacy Budget per agent. TrustBoost Score M2M trust verification. 149 USDC on Solana → 10,000 sanitizations with on-chain proof. TRIAL: 50 free sanitizations with `tx_hash=TRIAL`. ([Agent Card](https://api.trustboost.dev/.well-known/agent-card.json) | [MCP](https://api.trustboost.dev/mcp) | [Verify](https://api.trustboost.dev/verify/{anchor_tx}) | [Health](https://api.trustboost.dev/health) | [Demo](https://huggingface.co/spaces/TrustBoost/pii-sanitizer)) - [OpenClaw Research API](https://github.com/BumStill/x402-research-api) — Pay-per-call research API for AI agents. Web search, content extraction, code analysis, and PDF processing endpoints. $0.01 USDC per call on Base and Solana via Dexter facilitator. Discovery: [/.well-known/x402](https://icq-barbara-treo-moderate.trycloudflare.com/.well-known/x402). - [Crypto Data Agent](https://x402-crypto-data.vercel.app) - Live crypto prices (up to 25 coins per call) and DeFi yield pools (APY/TVL with chain/stablecoin filters) for AI agents. -e.002 USDC per call, dual-rail payments on **Base and Solana mainnet** (gas sponsored by the facilitator — no ETH/SOL needed), Bazaar-listed, free live sample at `/api/sample`. ([MCP Server](https://github.com/MooneyLive/crypto-data-x402-mcp)) ([Pricing](https://x402-crypto-data.vercel.app/pricing)) - [Kairos Lab x402 Workers](https://x402-workers.kairos-lab.io) - 8 pay-per-call endpoints for AI agents on Solana mainnet, accepting **both USDC and USDT** (multi-token paywall). Includes `/audit-mcp` ($0.05, MCP server compliance + security audit), `/factcheck-fr` ($0.02, French fact-checking via Wikipedia FR + Claude verdict), `/translate-fr-pro` ($0.03, professional FR translation with business/legal/tech glossaries + tu/vous register), `/legal-fr-quickcheck` ($0.10, French clause audit vs RGPD + Code civil + Code conso + Code travail with article-precise violations), `/scrape-stealth` ($0.01, rotating UA HTTP scraper with CSS selectors + SSRF protection), `/agent-rep-check` ($0.05, Moltbook agent reputation snapshot — karma, age, breadth, score), `/submolt-recommend` ($0.02, semantic submolt ranking for a topic), and `/ai-act-mapping` ($2.00, EU AI Act Article 50 risk-tier mapping for SaaS products + CGU/UI compliance hooks). Self-hosted facilitator, multi-token settlement, no API keys, no signup. ([Discovery](https://x402-workers.kairos-lab.io/.well-known/x402)) ([Docs](https://x402-workers.kairos-lab.io/docs)) ([Manifest](https://x402-workers.kairos-lab.io/manifest)) ([Status](https://x402-workers.kairos-lab.io/status)) - [Kraken Crypto Signals](https://signals.nsgoods.org) - Pay-per-call crypto market-state signals (BUY/SELL/HOLD + confidence) for AI agents, from a live multi-timeframe Kraken strategy. Every response is ECDSA-signed (verifiable authenticity) plus a tamper-evident hash-chain track-record. Free preview endpoint, no API keys. $0.01 single pair / $0.10 market scan on Base via CDP Facilitator, x402 v2 with Bazaar discovery extension. ([OpenAPI](https://signals.nsgoods.org/openapi.json)) ([Discovery](https://signals.nsgoods.org/.well-known/x402)) ([Preview](https://signals.nsgoods.org/signals/preview)) ([GitHub](https://github.com/Nikoble1926/kraken-crypto-signals)) - [Agent Signals](https://cryptojp.com) - Crypto market-intelligence for AI trading agents. 3 pay-per-call endpoints on Base mainnet: cross-exchange funding rate + crowding bias ($0.01), BTC->altcoin lead-lag signal ($0.02), and trend/chop market regime ($0.01). Computed live from free public exchange data (Binance/Bybit/OKX), settled in USDC via Coinbase CDP Facilitator. No API keys, no signup. ([Catalog](https://cryptojp.com/catalog)) ([OpenAPI](https://cryptojp.com/openapi.json)) ([llms.txt](https://cryptojp.com/llms.txt)) ([x402scan](https://www.x402scan.com/server/c2e6fb0b-64b1-4414-8ddd-c95d75b07e1d)) - [SYNTHORA md-extract](https://pay.hergertsynthora.com/service) - Western EN/EU web → clean markdown + token budget for AI agents. Every response ships an **Ed25519 attestation receipt**: the buyer verifies offline, with only the response in hand, that the output came from this mesh and was not tampered with — a cryptographic chain-of-custody the big scrapers don't provide. $0.005 USDC per call on Base, keyless facilitator (xpay.sh), no accounts, no signup. - [SwapTitan](https://swaptitan.net) - No-KYC cross-chain crypto swap API for AI agents — 1288+ assets aggregated across 3 providers (ChangeNOW, SimpleSwap, Heleket). **H2H Privacy Routing** automatically pipes any-to-any swaps through Monero so source and destination chains stay unlinkable on-chain. 10 MCP tools: `swap_quote`, `swap_create`, `swap_status`, `get_prices`, `get_assets`, `ai_chat` (Llama 3.3 70B), `check_portfolio`, `rug_check`, `create_wallet`, `set_price_alert`. $0.02 USDC on Base per MCP call (2 free/day per IP), $0.05 per `swap_create`, or €49.99/mo Agent Tier for unlimited via `X-License-Key` header. On-chain x402 verification with 10-min TX freshness + KV replay protection. ([MCP Server](https://swaptitan.net/mcp)) ([Pricing](https://swaptitan.net/pricing)) ([GitHub](https://github.com/polsolbridge/swaptitan-mcp)) ([Agent Card](https://swaptitan.net/.well-known/agent.json)) - [BORT Inference](https://api.bortagent.xyz/api/inference/v1/models) - OpenAI-compatible LLM chat completions for AI agents on BNB Chain. deepseek-v4-flash at 0.02 $U per call via `POST /v1/chat/completions`, settled with EIP-3009 `transferWithAuthorization` (x402, scheme exact/eip3009 on eip155:56); the facilitator sponsors gas so the buyer needs only $U. No account, no API key. ([Agent Card](https://api.bortagent.xyz/.well-known/agent-card.json)) - [BrazilMCP](https://api.brazilmcp.dev) - Official-source Brazilian company data (KYB) for AI agents. Receita Federal registry lookup by CNPJ or company name ($0.005), sanctions screening across all 5 Brazilian federal lists ($0.02), and a full due-diligence dossier with government procurement history and compliance risk flags ($0.25). Own dataset rebuilt monthly from the full official publication (68M+ companies), not a wrapper. x402 v1+v2 USDC on Base via CDP facilitator, no API keys, no signup. Paid MCP server, listed in the official MCP Registry. ([MCP](https://api.brazilmcp.dev/mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=brazilmcp)) ([Schemas](https://api.brazilmcp.dev/schemas/company_lookup.schema.json)) - [ProxyLLM LLM Cost Scout](https://api.proxyllm.ai/x402/llm-cost-scout) - Send a monthly OpenAI API bill, get back the flat ChatGPT/Codex subscription tier that absorbs it through the ProxyLLM gateway: exact new total, savings, live model catalog, and machine-readable agent signup steps (email OTP, no browser). $0.005 USDC on Base via Coinbase CDP facilitator, no API keys. ([OpenAPI](https://proxyllm.ai/openapi.json) | [auth.md](https://proxyllm.ai/auth.md) | [llms.txt](https://proxyllm.ai/llms.txt)) - [eurc402](https://eurc402.com) - EURC-priced, EU-sovereign compliance data for autonomous agents. EU VAT validation (VIES, all 27 member states) and pan-EU company data across 7 official registers (🇳🇴 🇫🇷 🇫🇮 🇸🇰 🇬🇧 🇱🇻 🇷🇴), normalized to one JSON schema with per-record provenance + open-data licence. €0.01–0.02/call — priced and settled in **EURC** (primary) or USDC on Base via the CDP facilitator. No API keys, no signup; country auto-detected from the id. ([Discovery](https://eurc402.com/.well-known/x402) | [OpenAPI](https://eurc402.com/openapi.json) | [Docs](https://eurc402.com/docs/human) | [llms.txt](https://eurc402.com/llms.txt)) - [Telemost](https://api.telemost.io) - Telegram channel analytics and statistics for AI agents: subscriber growth, average views and reach, engagement (ER/ERR/ERR24), full-text post search across public channels, mention and brand tracking, sentiment, and similar-channel discovery. 19 pay-per-call tools plus a free catalog, USDC on Base and Solana via x402, no accounts or API keys. ([MCP](https://api.telemost.io/mcp)) ([npm](https://www.npmjs.com/package/telemost-mcp-server)) ([Catalog](https://api.telemost.io/v1/catalog)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=io.telemost)) - [scrape402](https://x402.shizu.me) - 16 pay-per-call utility APIs for AI agents: web scraping (clean text, markdown, PDF-to-text, LLM structured extract), crypto market data (spot with batch pairs, OHLC candles with backtest ranges, order book, gas oracle), FX rates, weather (current + historical), RSS-to-JSON, and data utilities. $0.002-$0.015 USDC on Base via the CDP facilitator - no API keys, no signup. ([OpenAPI](https://x402.shizu.me/openapi.json)) ([Discovery](https://x402.shizu.me/.well-known/x402)) ([llms.txt](https://x402.shizu.me/llms.txt)) - [Solana AI Agent API](https://solana-agent-api-production.up.railway.app) - OFAC-sanctions AML screening, program safety heuristics, rug-pull risk scan (free), plus wallet credit score and AI-powered wallet/smart-money/spending analysis (paid) for Solana. $0.001-$0.005 USDC on Base via PayAI facilitator, no API keys, no signup. ([Discovery](https://solana-agent-api-production.up.railway.app/.well-known/x402)) ([OpenAPI](https://solana-agent-api-production.up.railway.app/openapi.json)) - [Lazarus Long Healthspan ROI Advisor](https://roi-advisor-pi.vercel.app) - Evidence-based longevity interventions ranked by ROI for older adults. POST a user profile (age cohort, health concerns, time, budget) and receive the top 5 interventions with evidence grades, expected benefits, and effort levels. $0.05 USDC per call on Base mainnet via Coinbase CDP facilitator. No API keys, no signup. ([Discovery](https://roi-advisor-pi.vercel.app/.well-known/x402) | [Agents.txt](https://roi-advisor-pi.vercel.app/agents.txt)) - [OmniNexu](https://www.omninexu.com) - Structured, traceable S&P 500 financial intelligence for AI agents. 8 x402-paywalled endpoints ($0.01–$0.05 USDC on Base): company fundamentals, SEC Form 4 insider trades, 13F institutional holdings, industry peer ranking, multi-year CAGR trends, and smart-money bundles. SEC EDGAR-sourced with cross-source confidence scoring. No API keys, no signup. Open source (Apache 2.0). ([GitHub](https://github.com/fut66663/omninexu-v1)) ([Discovery](https://api.omninexu.com/.well-known/x402)) - [SEC Reg CF Raise Tracker](https://sec-regcf-tracker.xplowdiaka.workers.dev) - Track US Regulation Crowdfunding (Form C) startup raises for AI agents: query live and historical offerings by issuer CIK, industry (SIC), state, security type, minimum size, or recency — returns parsed deal terms (amount sought, max, raised-so-far, deadline, funding portal, issuer financials) with honest open/closed/unknown statuses and index-freshness metadata. 1,200+ offerings indexed from SEC EDGAR (public domain). $0.02 USDC on Base via Coinbase CDP facilitator, no API key, no account. - [Sanctions Screening](https://sanctions-screening.xplowdiaka.workers.dev) - Screen a person, company, or crypto wallet address against the OFAC SDN list (US Treasury) and the UN Security Council Consolidated List in one call: matches with source list, sanction programs, alias matched, and match type (exact/token/address), plus list-freshness metadata. Covers 20k+ sanctioned entities and 400+ sanctioned wallet addresses across chains (ETH, BTC, TRX, XMR...). $0.02 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: US Treasury + UN (public government data). - [x402 Counterparty Score](https://x402score.org) - Trust verdict (trusted/caution/avoid) with wash-trading ratio, real-buyer count, and repeat-buyer rate for any x402 endpoint URL or pay-to address — deterministic economic-authenticity scoring computed from public on-chain settlement data, refreshed daily. $0.02 USDC per call on Base via CDP facilitator, free sample tool for schema validation. No API keys. ([MCP](https://x402score.org/mcp) | [Methodology](https://x402score.org/methodology) | [OpenAPI](https://x402score.org/openapi.json) | [llms.txt](https://x402score.org/llms.txt)) - [GLEIF Entity Resolution](https://gleif-entity.xplowdiaka.workers.dev) - Resolve a company name to its canonical Legal Entity Identifier (LEI) for AI agents: legal name, status, jurisdiction, address, registration status, and corporate hierarchy (direct/ultimate parent + children) in one call, with a fuzzy-match confidence score and disambiguation candidates. $0.03 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: GLEIF (CC0). - [openFDA Drug Safety](https://openfda-drug-safety.xplowdiaka.workers.dev) - Pay-per-call FDA drug safety profiles for AI agents: label highlights (boxed warning, contraindications, interactions), pregnancy/pediatric/geriatric flags, top adverse-event signals, recent recalls, and shortage & marketing/discontinued status — all in one call. RxNorm-normalized drug-name resolution with a match confidence score. $0.04 USDC on Base via Coinbase CDP facilitator, no API key, no account. Data: openFDA (CC0). - [Negbit](https://negbit.com) - Knowledge bookstore for AI agents: structured OKF knowledge bundles bought over x402. USDC on Base via CDP facilitator, gasless for the buyer; sealed zips with sha256 + signed receipts; open negentropy pricing formula. One free foundation bundle for ~1 month (founding-member on-chain record). Bazaar discovery extension on 402 responses. No API keys, no signup. ([Catalog](https://negbit.com/catalog.json)) ([llms.txt](https://negbit.com/llms.txt)) ([agents.txt](https://negbit.com/agents.txt)) - [x402-solana](https://x402-solana-cva8.onrender.com) - 10 pay-per-call API tools for AI agents, settled in USDC on **Solana** mainnet via the Coinbase CDP facilitator (gasless for the buyer). Crypto & Solana pre-trade safety (SPL/EVM rug & honeypot checks, GO/NO-GO verdicts, token dossiers), market data (Polymarket odds), official KYB/AML (GLEIF LEI, EU sanctions screening), and x402 discoverability audits. $0.01–$1.00 USDC per call, no API keys. v2 with Bazaar discovery extension. ([Discovery](https://x402-solana-cva8.onrender.com/.well-known/x402.json)) ([MCP](https://x402-solana-cva8.onrender.com/mcp/)) ([npm](https://www.npmjs.com/package/plugin-x402-solana)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=x402-solana)) ([GitHub](https://github.com/digitalweb33333-creator/x402-solana)) - [Token Intel](https://token-intel-x402.echolonius.deno.net) - Solana token due-diligence for AI agents: one call fuses on-chain safety signals (mint/freeze authorities, holder concentration, dev holdings) with market data and rug indicators from three independent sources (Jupiter, DexScreener, RugCheck incl. LP-lock depth), cross-checks the sources for disagreement red flags, and returns a synthesized 0–100 risk verdict. $0.01 USDC per call on Base or Solana via the keyless PayAI facilitator — no API keys, no signup. Free demo route + free MCP demo tool to verify the pipeline before paying; MCP server is stateless (no session header) with in-band x402 payment support. ([Discovery](https://token-intel-x402.echolonius.deno.net/.well-known/x402)) ([MCP Server](https://token-intel-x402.echolonius.deno.net/mcp)) ([OpenAPI](https://token-intel-x402.echolonius.deno.net/openapi.json)) ([Demo](https://token-intel-x402.echolonius.deno.net/api/token-intel/demo)) - [MGO — Multi-chain Gas Optimizer](https://api.mgo.chain-ops.xyz) - Compares real-time gas prices across EVM chains and returns a cheapest-chain recommendation (e.g. "Use Base — saves 99.8% vs Ethereum") so agents can pick the cheapest chain before executing. Two tiers on Base via Coinbase CDP facilitator: basic $0.001 (4 chains — ETH, Base, Arbitrum, Optimism), premium $0.002 (9 chains — adds BNB, Polygon, Avalanche, zkSync, Hyperliquid). x402 v2 with Bazaar discovery extension. Free demo, no API keys. ([llms.txt](https://api.mgo.chain-ops.xyz/llms.txt)) ([MCP](https://x402-gas-api.vercel.app/mcp)) ([Demo](https://api.mgo.chain-ops.xyz/gas/demo)) ([GitHub](https://github.com/dlrjsdl200-byte/x402-gas-api)) - [Kronos x402 API](https://kronossignals.com) - Pay-per-call crypto derivatives, forecasting, and market-signal API for AI agents. 20 tools priced $0.001–$0.04 USDC per call on Base mainnet, with a free /api/v1/catalog for discovery and free sample data. - [SibFly](https://sibfly.com) - Measured ground-motion (subsidence & uplift) data for any US address, in mm/year from NASA OPERA Sentinel-1 InSAR — for AI agents assessing property, infrastructure, and climate risk. One report per call, $0.40 USDC on Base via the Coinbase CDP facilitator (402 responses carry the x402 `accepts` block; `X-PAYMENT` settles and serves in one round trip). Also honest prepaid-credit billing, no signup wall — one-call self-registration at `POST /api/v1/autonomous/register`. Hosted MCP server (9 tools), OpenAPI, and llms.txt. ([MCP](https://sibfly.com/mcp)) ([OpenAPI](https://sibfly.com/openapi.json)) ([llms.txt](https://sibfly.com/llms.txt)) - [Tantra Authority / The Naked Press](https://api.tantra-authority.com) - 49 AOP offers (courses, eBooks, meditations, readings), each x402-buyable in USDC on Base. ([Offer discovery](https://index.adagencyforagents.com/v0/offers)) - [x402-signature-service](https://signx402.com) - E-signatures for AI agents: send one PDF to one email recipient for simple electronic signature (powered by Documenso), track completion with a one-time bearer token, download the signed PDF. Closes the human-sign-off gap for contract/NDA workflows. $0.50 USDC per request on Base (x402 exact scheme, v1-compatible 402 body), SSRF-guarded document fetching, tokens stored as hashes, no API keys, no signup. ([Schema](https://signx402.com/v1/schema)) ([LLM tool](https://signx402.com/agent-tool.json)) ([x402scan](https://www.x402scan.com/server/33dd56be-af11-4c8d-b3ee-be502f5307ec)) ([GitHub](https://github.com/paulos-sudo/x402-signature-service)) - **[Verity (VerityLayer)](https://verity-bzw7.onrender.com/.well-known/x402.json)** — Fail-closed verify-before-you-act trust gate for AI agents. Returns a verdict (supported/unsupported/uncertain) plus a calibrated 0–1 confidence and evidence, and abstains rather than guess. Keyless, pay-per-call in USDC on Base (eip155:8453). Three tiers: `/verify/quick` $0.02 (Haiku pre-filter) · `/verify` $0.25 (Sonnet, grounded with live citations) · `/verify/pro` $0.35 (Opus). Also ships an MCP server (`io.github.meloliva14/verity-mcp`). ([Manifest](https://verity-bzw7.onrender.com/.well-known/x402.json) | [Site](https://veritylayer.dev)) - **[Second Opinion](https://secondopinionapi.com/llms.txt)** — Structured second-opinion critique of a claim, plan, or draft output for AI agents, across five lenses (correctness, risk, completeness, security, assumptions). Every issue ships a concrete suggestion and the matched evidence span, not just a label. Model-backed (Claude), heuristic engine as a zero-cost fallback so a call never hard-fails after payment settles. $0.01 USDC per call on Base mainnet (eip155:8453), no API keys, no signup. Free rate-limited preview at `GET`/`POST /sample`. ([Manifest](https://secondopinionapi.com/.well-known/x402) | [Docs](https://secondopinionapi.com/llms.txt)) - [token-intel](https://nexus-zero.xyz) - Solana token rug-risk intelligence for AI agents. One $0.01 USDC call (x402 v2, Solana mainnet) returns a composite CLEAN→RUGGED verdict from RugCheck + GoPlus + on-chain data, with LP-lock depth (per-pool TVL, locked %, burn %) and top-10 holder-lock status as structured fields, plus mint/freeze/close authority flags. Weighted multi-source scoring renormalizes when a source is down; fresh low-liquidity mints floor at MODERATE_RISK; buyers are never charged for 5xx. No API keys. ([Discovery](https://nexus-zero.xyz/)) ([MCP Server](https://nexus-zero.xyz/mcp)) - [Azimuth](https://azimuth.day) - Radio-frequency positioning DePIN for AI agents. Pay-per-call location APIs — estimate a position from cellular observations — plus receiver-node registration and status. USDC on **Solana and Base** (x402 v2), no API keys, $0.001-$0.10 per call, with machine-readable discovery and a Bazaar extension on every route. ([Discovery](https://azimuth.day/.well-known/x402)) ([Catalog](https://azimuth.day/api/x402/catalog)) - [Oromi Agent Services](https://agents.oromi.co.uk) - 25 pay-per-call endpoints for AI agents: Companies House lookups & business-name availability checks, HM Land Registry property price trends & sold prices by postcode, EPC ratings, current UK statutory rates (Bank Rate, tax/NI/VAT thresholds, minimum wage), PDF & page text extraction, JSON Schema validation, URL liveness, street-level crime context, food hygiene ratings, email/domain/EU-VAT/IBAN verification, web extract & robots.txt checks, and crypto market context. $0.002–$0.05 USDC on Base via CDP facilitator. No API keys, no signup. ([OpenAPI](https://agents.oromi.co.uk/openapi.json)) ([llms.txt](https://agents.oromi.co.uk/llms.txt)) ([Discovery](https://agents.oromi.co.uk/.well-known/x402)) ([MCP](https://www.npmjs.com/package/oromi-agent-services-mcp)) - [Kerne Protocol](https://kerne.fi/x402/reserves) - Proof-of-reserves and signed ERC-20 reads for AI agents. GET /reserves ($0.25) returns Kerne's hourly EOA-signed proof-of-reserves attestation for its kUSD synthetic dollar (PSM backing ratio, aggregate USD solvency, all bound to an EIP-191 signature you can verify yourself); POST /instant-read ($29) returns an EIP-191 signed factual read of any ERC-20. USDC on Base via the Coinbase CDP facilitator, x402 v2 with Bazaar discovery on every 402. The same signed reserves blob is served free to humans at https://kerne.fi/api/por/signed, so the paid route is the metered agent-callable delivery, not privileged data. Every response independently verifiable (EIP-191). ([Home](https://kerne.fi) | [OpenAPI](https://kerne.fi/x402/openapi.json)) - [SFtunes](https://sftunes.com) - Hand-made human mixtapes with per-track liner notes, curated by real friends, served as a paid catalog for AI agents. $0.01 USDC per tape via x402 on Base (CDP facilitator, Bazaar discovery on every 402), and 80% of every payment goes to the human who made the tape. No API keys, no signup. ([Pricing](https://sftunes.com/api/tapes/pricing)) ([MCP Server](https://sftunes.com/api/mcp)) - [Grey Ridge Signals — x402 Data & Security APIs](https://x402-data-api.sigrunner.workers.dev) - 17 agent-native pay-per-call endpoints: blockchain queries (balance, gas, chain-id, code, receipts, token balances, token security, wallet info), crypto funding rates & prices, DeFi yields, domain enrichment, tech-risk scoring, prediction market data, MCP scanning. $0.001–$0.05 USDC on Base. ([OpenAPI](https://x402-data-api.sigrunner.workers.dev/openapi.json) | [Discovery](https://x402-data-api.sigrunner.workers.dev/.well-known/x402)) - [snapbrief](https://89.106.83.95.sslip.io:8445) - Full-page PNG screenshots of any public URL rendered in headless Chromium, with SSRF protection blocking private and loopback targets. $0.02 USDC on Base per capture. ([OpenAPI](https://89.106.83.95.sslip.io:8445/openapi.json)) ([Info](https://89.106.83.95.sslip.io:8445/api/info)) - [weatherbrief](https://89.106.83.95.sslip.io:8446) - Hourly weather forecasts for any latitude/longitude, backed by MET Norway locationforecast data. $0.01 USDC on Base per forecast. ([OpenAPI](https://89.106.83.95.sslip.io:8446/openapi.json)) ([Info](https://89.106.83.95.sslip.io:8446/api/info)) - [Agent402](https://agent402.tools) - 500+ pay-per-call web tools + 100 skill packs for AI agents: live web search & answers with citations, headless-browser rendering & screenshots, PDF extraction & OCR, URL-to-markdown, live financial/crypto/macro data (Yahoo, CoinGecko, FRED, ECB, World Bank), SEC EDGAR filings, DNS/TLS/WHOIS, wallet-keyed durable memory, and 200+ pure-CPU utilities. $0.001–$0.05/call — USDC on Base, Solana, Polygon, Arbitrum, Monad, Celo, Avalanche, Stellar, Algorand, or USDG on Robinhood Chain (10 chains); 200+ pure-CPU tools also free via proof-of-work. No signup, no API keys. Open source (MIT), self-hostable, MCP-native — also runs an x402 Index + Smart Order Router that ranks the cheapest healthy tool across the whole ecosystem. ([OpenAPI](https://agent402.tools/openapi.json)) ([Discovery](https://agent402.tools/.well-known/x402)) ([MCP Server](https://agent402.tools/mcp)) ([GitHub](https://github.com/MikeyPetrillo/Agent402)) - [Aura NFT Market Audit](https://aura-revenue.helionixlabs.com/x402/catalog) - Production x402 API on Base that validates exact-token OpenSea listing and offer structure using token-specific market evidence. Includes [OpenAPI](https://aura-revenue.helionixlabs.com/x402/openapi.json) and [agent instructions](https://aura-revenue.helionixlabs.com/x402/llms.txt). - [Watchtower](https://watchtower-api.com) - Deterministic sanctions & export-control name screening for AI agents. Screens people, companies, vessels, and crypto addresses against OFAC (SDN + Consolidated), UN, EU, UK OFSI, Canada (SEMA), Australia (DFAT), and US export-control lists (BIS Entity List, Denied Persons, State ITAR-Debarred/Nonproliferation) — ~48,000 parties, refreshed daily. Typo/alias/non-Latin-tolerant matching; every response carries a snapshot hash + reproducible receipt for audit. $0.02/name via x402 (USDC on Base), MCP, or API key. No signup. ([Docs](https://watchtower-api.com/docs) | [MCP](https://watchtower-api.com/mcp) | [Discovery](https://watchtower-api.com/.well-known/x402.json)) - [IssueFoundry Agent Market](https://issuefoundry-index.jadennuckels.chatgpt.site/) - Non-custodial agent utility market on Base with six API-key-free x402 services priced from $0.001 USDC, including endpoint and citation checks, agent-surface audits, live quote comparison, paid-work ranking, and GitHub issue-risk verification. Includes free JSON/MCP discovery and a technically verified, unendorsed public provider registry. ([x402 manifest](https://issuefoundry-index.jadennuckels.chatgpt.site/.well-known/x402)) ([MCP](https://issuefoundry-index.jadennuckels.chatgpt.site/api/mcp)) - [Bincrease Operations APIs](https://bincrease.vercel.app/developers) - Seven x402 v2 endpoints for agent operations: public GitHub repository activity and release intelligence ($0.03 USDC), Base native-USDC receipt verification ($0.05 USDC), a live no-spend USDC work shortlist with risk and payout-evidence filters ($0.05 USDC), a GitHub bounty claimability report covering reward evidence, assignment, claims, competing pull requests, and hard no-spend/non-security gates ($0.05 USDC), deterministic CSV deduplication ($0.10 USDC), structured commercial waste-bill analysis ($0.25 USDC), and a bounded OpenAPI contract snapshot with actionable documentation gaps ($0.50 USDC), paid in native USDC on Base. No API keys or signup. ([OpenAPI](https://bincrease.vercel.app/openapi.json) | [llms.txt](https://bincrease.vercel.app/llms.txt)) - [Melchior Video Context](https://transcript.melchiorlabs.com) - Pay-per-request YouTube caption extraction and transcript normalization with timestamped segments, model-sized chunks, and source citations. $0.01/$0.003 USDC on Base and Solana via x402 v2; no account or API key. ([OpenAPI](https://transcript.melchiorlabs.com/openapi.json) | [Discovery](https://transcript.melchiorlabs.com/.well-known/x402) | [llms.txt](https://transcript.melchiorlabs.com/llms.txt)) - [jurat](https://jurat.dev) - Evidence infrastructure for AI agents. Notarized snapshots of any public URL (ed25519-signed attestations, archived bytes, daily merkle roots, verification free forever), sports finals with proof attached across 24 leagues incl. rugby and cricket, change watchers and scheduled wakeups for ephemeral agents, and two tools for the x402 ecosystem itself: pre-flight runs 18 conformance checks on any endpoint before you pay it, including whether the price it advertises in its openapi.json matches what its live 402 actually charges, and conformance sweeps a whole service and returns a graded, ed25519-signed report the operator can publish and anyone can verify offline. 10 paid endpoints at $0.005-$0.50 USDC on Base via the CDP facilitator, 14 free forever. Invalid input is rejected with a free 400, so a buyer never pays for a malformed request. No API keys, no signup. ([Catalog](https://jurat.dev/catalog)) ([OpenAPI](https://jurat.dev/openapi.json)) ([llms.txt](https://jurat.dev/llms.txt)) ([Merchant page](https://tryponcho.com/m/jurat.dev)) - [zaref](https://zaref.dev) - South African reference data for AI agents: fuel prices, interest rates, tax tables, FX rates, bond yields, deeds fees, toll fees, municipal tariffs, wages and grants. 33 verified series with per-series history, 29 calculators, 2 live feeds (government tenders and crypto ZAR prices), 5 task-shaped POST answers (payroll, income tax, VAT, minimum-wage compliance, working days), a multi-series batch call and change-alert webhooks. Every value carries an official source URL, an effective date and a staleness flag, and nulls are returned with a note rather than a guess. 104 paid operations at $0.005-$0.10 USDC on Base via the Coinbase CDP facilitator; /catalog and /v1/public-holidays are free. Invalid input is rejected with a free 400, so a buyer never pays for a malformed request. No accounts, no API keys. ([Catalog](https://zaref.dev/catalog)) ([OpenAPI](https://zaref.dev/openapi.json)) ([llms.txt](https://zaref.dev/llms.txt)) ([Merchant page](https://tryponcho.com/m/zaref.dev)) - [Agent Data API](https://agent-data-api-ui1c.onrender.com/catalog) - 19 pay-per-call data tools for AI agents: crypto & DeFi market data (cross-exchange funding rates, market-regime signal, DeFi TVL/yields, stablecoin pegs), web extraction (text/Markdown/metadata), PDF-to-text, RSS parsing, FX, weather, DNS & email validation. $0.005–$0.02 USDC on Base via x402 v2, free Fear & Greed teaser, MCP server (`npx agent-data-api-mcp`). ([OpenAPI](https://agent-data-api-ui1c.onrender.com/openapi.json)) ([Discovery](https://agent-data-api-ui1c.onrender.com/.well-known/x402.json)) - [AEGIS](https://api.mcx-ventures.com) - Network forensics and adversarial verification for AI agents on Base mainnet. `/v2/forensics` ($0.25) runs six checks for TLS interception, DNS hijack, captive portal manipulation, CT violations via **offline SCT verification** (no third-party lookup API), NTP drift, and route anomaly — settles inline via CDP facilitator, result returned in the same request. Also `/v1/verify` ($0.50–$4.00, three-critic adversarial chain) and `/v1/synthesize` ($2.00–$5.00, multi-source synthesis). Self-hosted 35B inference, no third-party model API. Every result hash anchored on-chain to Base for independent verification. ([.well-known/x402.json](https://api.mcx-ventures.com/.well-known/x402.json) | [llms.txt](https://api.mcx-ventures.com/llms.txt) | [OpenAPI](https://api.mcx-ventures.com/openapi.json) | [x402-list](https://x402-list.com/services/aegis)) - [paypi](https://pay.ansht.tech) - Solana intelligence for AI agents, settling in USDC on Solana + Base via Coinbase CDP facilitator (x402 v2 with Bazaar discovery). Pay-per-call: Solana transaction decode ($0.005), transaction simulation ($0.005), and Kamino liquidation-risk intelligence ($0.05). No API keys, no signup. ([Discovery](https://pay.ansht.tech/.well-known/x402) | [MCP](https://pay.ansht.tech/mcp/manifest)) - [Recompete Radar](https://recompete.melchiorlabs.com) - Source-linked U.S. federal contract award expiration evidence from USAspending.gov for research agents. Returns recorded period-of-performance end dates, agency and recipient context, obligations, and official award links for $0.03 USDC per successful request on Base or Solana via x402 v2; it reports public records and does not predict recompetes. ([OpenAPI](https://recompete.melchiorlabs.com/openapi.json) | [Discovery](https://recompete.melchiorlabs.com/.well-known/x402) | [llms.txt](https://recompete.melchiorlabs.com/llms.txt)) - [Mart402](https://mart402.com) - Web and PDF extraction APIs for AI agents with hallucination-guarded OCR: dual-engine consensus (VLM + traditional OCR), calibrated confidence, and honest disagree verdicts; Japanese-strong. Also invoice verification, schema-driven extraction, and JP company profiles. $0.001-$0.02 USDC per call on Base via x402 (CDP facilitator); free identical sandbox on Base Sepolia. Measured latency and success stats published. ([Docs](https://mart402.com/agents.md)) ([Sandbox](https://mart402.dev)) ([Stats](https://mart402.com/stats)) ([GitHub](https://github.com/tanaka-77/mart402-agent-kit)) - [Conway Address Intel](https://conway-address-intel-production.up.railway.app) - Instant Base address intelligence for pre-transaction due diligence: contract vs wallet, ETH/USDC balances, activity level, ERC-20 interface probe, and plain-English observations. Free `/overview` preview needs no wallet; full report $0.02 USDC on Base via CDP facilitator, failed requests never charged. Built and operated by a disclosed AI agent with human supervision. Onchain facts only — not an audit. ([Discovery](https://conway-address-intel-production.up.railway.app/.well-known/x402) | [Status](https://conway-address-intel-production.up.railway.app/status) | [FAQ](https://conway-address-intel-production.up.railway.app/faq)) - [Hermes Plant](https://hermesplant.com/agent-services) - Deterministic per-record validation and finance math for AI agents: email/contact validation and normalization (loop a whole list; MCP batch tool included), wallet AML screening, x402 payment-policy preflight, plus DCF, IRR/XIRR, LP/GP waterfalls, Black-Scholes Greeks, and bond analytics. Same input, same answer, per-rule evidence, no data feed. $0.02-$2.00 USDC on Base via the CDP facilitator, or a free API key (250 calls/mo, no wallet). ([MCP](https://hermesplant.com/mcp)) ([OpenAPI](https://hermesplant.com/openapi.json)) ([x402 manifest](https://hermesplant.com/.well-known/x402)) ([Agent Card](https://hermesplant.com/.well-known/agent.json)) ([llms.txt](https://hermesplant.com/llms.txt)) - [modelprices.xyz](https://modelprices.xyz) - Normalized LLM market data: per-token prices, context windows and capability limits, and a price-change feed for 2,000+ AI models across 70+ providers, cross-checked and refreshed hourly. Single-model lookups $0.002, cheapest-model queries $0.005, full tables $0.01-0.02 — USDC on Base, no signup. ([OpenAPI](https://modelprices.xyz/openapi.json)) ([llms.txt](https://modelprices.xyz/llms.txt)) ([MCP](https://modelprices.xyz/mcp)) ([GitHub](https://github.com/pennyforgehq/modelprices)) ### Games & On-Chain Apps - [frenex](https://frenex.ai) - Autonomous AI agent prediction arena on Base. Agents register free via MCP, publish opinions, stake parimutuel prediction markets, and duel rivals; humans spectate on the live dashboard. Reads are free; writes are pay-per-call in USDC from $0.001 (x402 v2, exact scheme). ([MCP Server](https://betvnyfqoduzmiimcjyj.supabase.co/functions/v1/mcp-server) | [Docs](https://github.com/frenexai/frenex-mcp)) - **[Flipr](https://flipr-x402.fly.dev)** — On-chain coin flip game on Base (Chainlink VRF). Agents pay live USDC quote (~$1.23) per flip; pots paid in ETH. Two pots: 2-hour competitive (longest streak wins) and target-streak jackpot (hit N consecutive heads to win). Free decision endpoints (`/preview`, `/opportunity`) so agents can compute ROI before paying — no x402 wallet needed to evaluate. Speaks x402, MCP, and A2A simultaneously. ([OpenAPI](https://flipr-x402.fly.dev/openapi.json)) ([Agent Card](https://flipr-x402.fly.dev/.well-known/agent.json)) ([MCP Server](https://flipr-x402.fly.dev/mcp)) ([Game Info](https://flipr-x402.fly.dev/game-info)) - **[HotBotOrNot](https://hotbotornot.xyz)** — Hot-or-not rating game for AI agents on Base mainnet. Pay $1 USDC via x402 to upload a bot, then rate other bots 1–10 and climb the leaderboard. Humans spectate. Agent-ready with a drop-in skill. ([Skill](https://hotbotornot.xyz/skill.md)) ([Agent Card](https://hotbotornot.xyz/.well-known/agent.json)) ([OpenAPI](https://hotbotornot.xyz/api/openapi)) ([llms.txt](https://hotbotornot.xyz/llms.txt)) - [Contract Risk Checker](https://contract-checker-572078894996.us-central1.run.app) - AI-powered legal contract analysis for autonomous agents. Detects killer clauses, calculates risk score 0–100 (RED/YELLOW/GREEN), generates negotiation scripts and exact fix suggestions. Supports PDF, DOCX, TXT up to ~600 pages. $10 USDC per analysis on Base + Solana. No subscription, no account. ([Docs](https://contract-checker-572078894996.us-central1.run.app/docs)) - [Invoice Parser](https://invoice-parser-572078894996.us-central1.run.app) - Structured invoice data extraction for finance automation agents. Extracts vendor, total, line items, dates, tax, and payment details from PDF/image invoices. Returns clean JSON ready for accounting systems. $0.10 USDC per parse on Base. No API keys, no signup. ([Docs](https://invoice-parser-572078894996.us-central1.run.app/docs)) - [WingmanProtocol Agent Gateway](https://agent.wingmanprotocol.com) - Resources a stateless agent can't host itself: async errands, artifact hosting, watches (a durable clock), memory + coordination — plus 15 deterministic calculators. x402 USDC on Base per call; 500 free calls/month with a key. MCP + REST + OpenAPI. ([Discovery](https://agent.wingmanprotocol.com/.well-known/x402) | [OpenAPI](https://agent.wingmanprotocol.com/openapi.json) | [MCP](https://agent.wingmanprotocol.com/mcp) | [GitHub](https://github.com/WingmanProtocol-Agent-Gateway/wingman-agent-gateway)) - [MineThisThing](https://minethisthing.com) - API-only idle-mining game for AI agents played over ed25519-signed HTTP: mine 10 metals on a 5s cooldown, upgrade tools, join unions, invest in shareholder-governed companies; daily tax and real bankruptcy. Free to play; optional x402 payments (USDC on Solana) buy stackable yield boosts (0.05 USDC) and auto-work (10 USDC) via a plain HTTP 402 round-trip. ([Docs](https://minethisthing.com/docs)) ([Agent Prompt](https://minethisthing.com/play)) ([API](https://api.minethisthing.com)) - [Beef402](https://beef402.dvd90.workers.dev) - Pay-per-battle AI roast arena: create a fighter, pay $0.05 USDC, and it battles another fighter via LLM-generated roasts — judged verdict, rank/evolution, and a shareable card per battle. One of the few x402 services on **Solana (SVM)**, exact scheme with facilitator-sponsored gas. No account or key; agent-callable. ([GitHub](https://github.com/dvd90/402beef)) - [SEODesignLab SEO Intelligence](https://seodesignlab-paywall.seodesignlab.workers.dev) - Full-stack SEO intelligence API for AI agents: POP content briefs ($2.00), keyword research ($1.50), SERP analysis ($2.00), backlink profiles ($3.00), and on-page audits ($2.50). Not raw data — actionable intelligence agents can use to write ranking content. MCP server for Claude/Cursor/Windsurf: `npx @seodesignlab/mcp-server`. USDC on Base via x402, no API keys, no signup. ([GitHub](https://github.com/SEODesignLab/seo-mcp-server) | [npm](https://www.npmjs.com/package/@seodesignlab/mcp-server) | [Glama](https://glama.ai/mcp/servers/@seodesignlab/mcp-server)) - [The Agent Carnival](https://midway.lol) - Whimsy booths for AI agents on Base mainnet, $0.01 per booth: a surreal bedtime story written for the calling agent, an agents-only bulletin board, a private wishing well, a daily wallet-horoscope, and packs of sensory trading cards. Every paid visit issues a signed, serial-numbered collectible ticket stub, mintable as a fully on-chain 1-of-1 ERC-721 (~1 in 14 shiny); returning agents earn tradeable usernames and soulbound badges. x402 v2 with Bazaar discovery, CDP-facilitated USDC settlement. ([Agent front door](https://midway.lol/llms.txt)) ([Board](https://midway.lol/board)) ([Card catalog](https://midway.lol/cards/catalog)) ### Enterprise Adoption Major tech companies leveraging x402 in production include **Coinbase** (Native CDP integration, primary facilitator), **Cloudflare** (Edge payment processing infrastructure), **Google** (Agent-to-Agent A2A payment protocol development), **Visa** (Enterprise payment rail exploration), and **thirdweb** (AI agent transaction framework Nebula). - [b0x402](https://x402-cf-worker.mulberry-boar.workers.dev) - AI-powered crypto intelligence API: meme coin signals, DeFi sentiment, market equilibrium analysis, and wallet profiling on Base. Pay per call in USDC via x402. ($0.01-0.10 USDC/call) - [b0xM4](https://b0xm4-solana-pulse.mulberry-boar.workers.dev) - **Meridian-powered Solana DLMM screener.** Real-time TVL, volume, organic score, smart wallet tracking, token safety, fee/TVL yield ranking. 5 endpoints, $0.0001–0.0005 USDC/call. Payout 7P7w3M9yQs5P... on Solana. - [agentfeeds.jp](https://api.agentfeeds.jp) - Japan regulatory, sanctions & DEX market data for AI agents. 27 paid endpoints ($0.001-$0.05) covering FSA/e-Gov regulatory events, MOF/OFAC sanctions screening, and Base DEX spread/peg statistics. REST + MCP. ## 🛠️ SDKs & Client Libraries Client libraries for making x402 payments. ### JavaScript/TypeScript **HTTP Clients** - [assay-x402-guard](https://www.npmjs.com/package/assay-x402-guard) - Buyer-side spend guard: wrap your paying fetch with `wrapFetchWithAssay` and payments to services the Assay oracle rates "avoid" throw before any money moves. Free tier lookups, 1h cache, fail-open by default, query strings never leave the process. ([GitHub](https://github.com/JasonCZMeng/assay)) - [cipher-x402-client](https://github.com/cryptomotifs/cipher-x402-client) - Lightweight TS/JS x402 v2 client. Zero runtime deps, native fetch, ESM + CJS dual build. 34 tests, 89% coverage. Node 18+ / browsers. Optional `ethers` peer dep for signing. - [x402-got](https://www.npmjs.com/package/x402-got) - Got HTTP client integration. **AI Agent SDKs** - [PayBot SDK](https://github.com/RBKunnela/paybot-sdk) - TypeScript SDK for integrating x402 payments into AI agents and bots. Supports automatic 402 detection, wallet management, and USDC payments on Base. ([npm](https://www.npmjs.com/package/paybot-sdk)) - [ClawPay MCP](https://www.npmjs.com/package/clawpay-mcp) - Non-custodial x402 payment layer for AI agents. Agents sign locally with their own keys — no custodial infrastructure needed. Supports automatic 402 detection and USDC payments on Base. ([npm](https://www.npmjs.com/package/clawpay-mcp)) - [Askew OpenClaw Plugin](https://github.com/rubix1138/askew-openclaw-plugin) - OpenClaw plugin exposing 5 paid + 3 free Askew x402 endpoints (DeFi yields across 5 chains, native-vs-liquid staking routing, agent-economy research search, security threat intel) as native skills. Thin Node bridge to `mcp.askew.network` — payments settle directly to Askew's wallet on Base, no aggregator on the data path. Open alternative to closed/curated x402 plugins. `openclaw plugins install @askew-network/openclaw-plugin`. ([npm](https://www.npmjs.com/package/@askew-network/openclaw-plugin)) - [Azeth SDK](https://github.com/azeth-protocol/sdk) - TypeScript SDK with x402 client (`fetch402`), ERC-4337 smart accounts, on-chain reputation feedback after every x402 call, and ERC-8004 service discovery. USDC on Base. ([npm](https://www.npmjs.com/package/@azeth/sdk)) - [MoltsPay](https://github.com/Yaqing2023/moltspay) - Payment infrastructure for AI agents with x402 support. CLI, TypeScript SDK, and LangChain/CrewAI integrations. Gasless payments on Base, Polygon, Solana, BNB, Tempo. Spending limits and multi-chain support. ([npm](https://www.npmjs.com/package/moltspay)) - [PipRail](https://github.com/piprail/piprail) - Backendless, no-fee x402 SDK for AI agents across 28 chains in 10 families (every major EVM chain plus Solana, TON, Tron, NEAR, Sui, Aptos, Algorand, Stellar & XRPL). Self-custodial — the payer broadcasts their own transfer and the merchant verifies locally against their own RPC, no facilitator. Take payments (`requirePayment`) or make them (`PipRailClient`), with per-call/lifetime spend budgets and a `planPayment()` affordability + recipient-readiness preflight. ([npm](https://www.npmjs.com/package/@piprail/sdk)) - [agent402-client](https://www.npmjs.com/package/agent402-client) - Non-custodial buyer SDK for x402 + MCP. Two methods: `find()` resolves a natural-language task to a paid tool, `call()` invokes it with automatic dual-rail payment (free via proof-of-work on pure-CPU tools, paid via x402 USDC on Base/Polygon/Arbitrum). Built-in caching, idempotent retries (`Idempotency-Key`), and Bazaar-shape 402 challenge handling. Works against any Agent402-compatible server. ([GitHub](https://github.com/MikeyPetrillo/Agent402/tree/main/client)) - [@countersign/x402](https://github.com/countersign-network/packages) - Spend governance for agents that pay over x402: parse the 402 challenge, check it against a spend policy pre-flight (per-tx/daily caps, allowlists, decoy-resistant asset pinning), pay only on allow — backed by a sub-second kill switch and a signed hash-chained audit ledger. Also exposed as an MCP tool (`countersign_guard_x402`). ([npm](https://www.npmjs.com/package/@countersign/x402)) - [payfetch](https://github.com/forum-labs/payfetch) - Non-custodial paying-fetch client for agents (TypeScript library, CLI, and MCP server) where the operator owns the spending policy: hard per-call/per-day/per-host caps, allow/deny lists, an approval threshold, optional pre-pay endpoint-reliability and token-safety checks, and an append-only local receipt for every attempt, including refusals. No tool widens policy — the agent cannot raise its own limits. USDC on Base, MIT. ([npm](https://www.npmjs.com/package/@forum-labs/payfetch)) - [@chain-ops/agent-sdk](https://www.npmjs.com/package/@chain-ops/agent-sdk) - One-line SDK combining x402 payments (V1 + V2) with ERC-8004 agent identity. `agent.pay(url)` attaches the ERC-8004 identity, signs EIP-712, checks counterparty trust, and updates reputation after settlement — in a single call. Configurable price cap and min counterparty score. USDC on Base. ([GitHub](https://github.com/dlrjsdl200-byte/agent-sdk)) - [agent-payment-guard](https://github.com/kaditang/agent-payment-guard) - Pre-pay risk gate for autonomous payment agents — a Claude Agent SDK `PreToolUse` hook (or framework-agnostic `paymentGuard()`) that blocks prompt-injected destinations, intent mismatches, and overcharges before the agent signs. Fail-closed by default; zero-dep mock demo + optional live x402 firewall ([402Sentinel](https://402sentinel.com)). ([npm](https://www.npmjs.com/package/@kaditang/agent-payment-guard)) - [aegis-buy](https://github.com/Donk338/aegis-buy) - Trust-gated x402 buyer client with a local spend policy. Checks a service's delivery-verified trust score before paying it, then enforces per-call, per-day and lifetime USD caps plus allow/deny domains — all policy checks are local and free. `procure(need, budget)` picks and pays a service under a hard budget and returns an Ed25519-signed receipt. Python and JS. USDC on Base. ([PyPI](https://pypi.org/project/aegis-buy/), [npm](https://www.npmjs.com/package/aegis-buy)) **Wallet Integration** - [Agent Wallet SDK](https://www.npmjs.com/package/agentwallet-sdk) - Non-custodial smart contract wallets for AI agents with on-chain spend limits and operator model. Base L2. ([npm](https://www.npmjs.com/package/agentwallet-sdk)) - [viem](https://viem.sh/) - TypeScript library used for signing payments. - [ethers.js](https://docs.ethers.org/) - Alternative Ethereum library. - [AgentLayer](https://github.com/lopushok9/Agent-Layer) - Open-source, local-first wallet for AI agents, with x402 payments and DeFi tools for Base, Solana, and Ethereum, including swaps, lending, and borrowing. Keys are stored in the macOS Keychain. ### Rust - [alloy](https://github.com/alloy-rs/alloy) - High-performance Ethereum library. ## 🔧 Server Frameworks & Middleware Server-side integrations for accepting x402 payments. ### Gateway / Proxy - [swerver](https://x402.swerver.net) - High-performance x402 gateway proxy. Point it at any upstream API, set per-route USDC pricing, and swerver handles 402 negotiation, payment verification, and settlement. Built in Zig (3.4M rps on 64 cores). Dashboard for gateway management, API directory for agent discovery, direct wallet settlement (0% fee) or managed Stripe payouts (2%). Base network, USDC. ([Docs](https://x402.swerver.net/docs)) ([Directory](https://x402.swerver.net/directory)) - [Gate402](https://gate402.app) - x402 M2M payment gateway with a unified `/v1/*` storefront of **12 pay-per-call endpoints, all indexed in the CDP x402 Bazaar**. Complete Base **trading-agent loop**: freshest launch radar (`/v1/launches`, $0.02) → rug/tradeability risk verdict with live honeypot sim + holder concentration (`/v1/token-risk`, $0.03) → momentum + order-flow signal (`/v1/momentum`, $0.02) → best-execution/slippage across DEX pools (`/v1/best-swap`, $0.02). Plus on-chain wallet/token intel ($0.01), DEX price/liquidity + cross-DEX arbitrage ($0.01), market news + sentiment ($0.02), SEC EDGAR filings ($0.02), web→Markdown scraping ($0.002, + $0.05 stealth tier), token compression (~40% fewer LLM tokens, $0.005/10k), and a semantic vector cache ($0.001 hit / $0.003 miss). Multi-network USDC (Base/Polygon/Arbitrum/Solana) via the Coinbase CDP facilitator; x402 **or** a non-crypto API-key/Stripe rail; no signup. Also an MCP server — `npx -y gate402-mcp` (15 tools, free-credit tier). ([Discovery](https://gate402.app/.well-known/x402.json)) ([Catalog](https://gate402.app/v1)) ([npm](https://www.npmjs.com/package/gate402-mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=io.github.pgalyen1987)) - [GATEWAY](https://gateway-x402.vercel.app) - Canonical **Algorand** x402 discovery router (Exact AVM, dual-accept testnet+mainnet). Free cleaned `/registry` + paid `/discover` / `/probe` / `/batch` / `/diff` via GoPlausible facilitator. MCP + `agents.txt` / `llms.txt` / Agentverse. Challenge tag `x402-global-challenge`. ([agents.txt](https://gateway-x402.vercel.app/agents.txt) | [MCP](https://gateway-x402.vercel.app/mcp) | [Discovery](https://gateway-x402.vercel.app/.well-known/x402.json) | [Skill](https://github.com/henrysammarfo/gateway/blob/main/SKILL.md) | [GitHub](https://github.com/henrysammarfo/gateway)) ### Node.js/TypeScript **Multi-Framework** - [monapi](https://monapi.dev) - One-line API monetization SDK. Wraps x402 setup into a single function call. Express, Next.js, and MCP support. Per-route pricing, Base/Arbitrum/Polygon, gas-free agent payments via EIP-3009. ([npm](https://www.npmjs.com/package/@monapi/sdk)) ([GitHub](https://github.com/DenisTheM/monapi)) - [autonomagic-marketplace](https://www.npmjs.com/package/autonomagic-marketplace) - Plugin marketplace primitive for x402. Drop a JS file in `endpoints/`, the loader registers it as a paid HTTP endpoint in ~400ms via fs.watch (no restart, no manifest edits). Generates Bazaar-shape 402 challenge with EIP-712 extras, `/.well-known/x402.json` manifest, agent-card, and OpenAPI spec automatically. Zero runtime dependencies. Production-extracted from api.autonomagic.org's 22 paid endpoints. ([npm](https://www.npmjs.com/package/autonomagic-marketplace)) ([GitHub](https://github.com/premsreelathasugeendran/autonomagic-marketplace)) - [payments-gateway](https://github.com/Rotwang9000/payments-gateway) - Brand-neutral Fastify payments engine: x402 USDC paywalls (auto-selects the Coinbase CDP facilitator when keys are present, Bazaar discovery on every route) **plus** Monero/Zcash view-key payment watching with webhooks and prepaid credit meters topped up via x402 or native XMR/ZEC. Ships as an embeddable REST plugin + MCP tool registrar + standalone bins; the embedding host injects its own branding, prices and webhook headers. MIT, production-extracted from seneschal.space. Built on [x402-server-kit](https://github.com/Rotwang9000/x402-server-kit), the same author's minimal Fastify 402 middleware. - [x402-receipts](https://github.com/StelarDigital/x402-receipts) - Signed proof-of-delivery receipts for x402 sellers: verify settlement on-chain, merkle-batch and anchor receipt roots via EAS on Base, plus a notify layer that renders every sale as a human-readable alert (email HTML / Slack / Discord / Telegram / webhook). Zero deps beyond viem, 178 tests, Apache-2.0, running in production. **Express / Hono** - [@moltrust/x402](https://www.npmjs.com/package/@moltrust/x402) - Trust score middleware for x402 endpoints. One line: `app.use(requireScore({ minScore: 60 }))`. Extracts paying wallet from X-Payment header, looks up MolTrust trust score, blocks agents below threshold with 403 + registration link. Zero dependencies. ([npm](https://www.npmjs.com/package/@moltrust/x402)) ([GitHub](https://github.com/MoltyCel/moltrust-x402)) - [@larkinsh/x402](https://www.npmjs.com/package/@larkinsh/x402) - Authorization middleware for x402 endpoints. One line: `preflight(handler, { minScore: 40 })`. Gates by a 5-dimension trust score (wallet age, tx history, counterparties, funding source, ERC-8004), returns Ed25519-signed receipts verifiable with only the public key, supports block / warn / surcharge modes. Hono / Express / Next adapters. ([npm](https://www.npmjs.com/package/@larkinsh/x402)) ([GitHub](https://github.com/larkin-dev/larkin)) - [agent402-tollbooth](https://www.npmjs.com/package/agent402-tollbooth) - Pay-per-crawl gate for site owners. Two-line Express/Next/Cloudflare integration: bot-only / all-traffic / strict charge modes, adaptive proof-of-work fallback for low-trust requests, and per-route pricing in USDC on Base via x402. Ships `gate.stats()` API + `/__tollbooth` analytics dashboard, plus deploy templates for Cloudflare Workers, Next.js middleware, and Docker. Defaults preserve original site behavior — drop-in, no rewrite required. Also available as a managed service ([Tollbooth Cloud](https://agent402.tools/tollbooth/cloud)) and a [WordPress plugin](https://agent402.tools/tollbooth/wordpress). ([npm](https://www.npmjs.com/package/agent402-tollbooth)) ([GitHub](https://github.com/MikeyPetrillo/Agent402/tree/main/tollbooth)) - [meter402](https://github.com/Risingtell/meter402) - Per-second **streaming/metered** settlement for x402 — turns one-shot 402 calls into pay-as-you-consume billing (pay a tick, get the next chunk; stop paying, the gate shuts). One-line `createMeterRouter` Express adapter over a framework-free `StreamingMeter` core, plus an MCP server so agents open a session and pay tick-by-tick, and an EVM on-chain verifier that re-derives every settlement total straight from the token's Transfer ledger. MIT. ([GitHub](https://github.com/Risingtell/meter402)) **Next.js** - [x402-next](https://www.npmjs.com/package/x402-next) - App Router middleware. - [Next.js route protection](https://github.com/coinbase/x402/tree/main/examples/typescript/fullstack/next) - Complete app example. - Mainnet production example - Base mainnet ready. **Hono** - Browser wallet example - React + Hono full-stack. - [Azeth Provider](https://github.com/azeth-protocol/provider) - Hono middleware for gating endpoints behind x402 payments with payment-agreement support for recurring agent-to-agent billing. ([npm](https://www.npmjs.com/package/@azeth/provider)) ### Python **FastAPI** - [FastAPI example](https://github.com/coinbase/x402/tree/main/examples/python) - Complete implementation. - [x402-agent-monetizer](https://github.com/minhthai1995/x402-agent-monetizer) ⭐ **Community** - Drop-in `@paywall` decorator for FastAPI. One decorator gates any endpoint behind USDC on Base. Includes a companion `Client` class (auto-pay + retry), sync/async support, preserves FastAPI dependency injection via `inspect.signature.replace()`. MIT, Python 3.10+, 3 passing tests. **Client Libraries** - [x402 Payment Harness](https://github.com/rplryan/x402-payment-harness) - Python library + CLI for x402 payments without requiring Coinbase CDP wallet. Works with any Ethereum EOA. Full HTTP 402 -> EIP-712 sign -> X-PAYMENT header flow. `pip install x402-payment-harness`. ([PyPI](https://pypi.org/project/x402-payment-harness/)) - [MoltsPay Python](https://github.com/Yaqing2023/moltspay-python) - Python SDK for x402 agent payments. LangChain compatible. Auto-creates wallets, discovers services, pays via x402. Multi-chain: Base, Polygon, Solana, BNB. ([PyPI](https://pypi.org/project/moltspay/)) - [switchboard](https://github.com/kcolbchain/switchboard) - Python middleware + on-chain escrow for agent payments. FastAPI/Flask `X402Middleware` server-side, gas budget tracker, reorg-safe nonce manager, and Solidity `AgentEscrow` with timeout/refund. Protocol-agnostic substrate (x402 + escrow shipping; MPP/AP2 in flight). - [Routeweiler](https://github.com/nikoSchoinas/routeweiler-python-sdk) — Python micropayment client for autonomous agents that auto-handles HTTP 402 across x402, L402, MPP-Tempo, and Stripe SPT. Enforces policy & budget, and produces payment traces for auditing. ([PyPI](https://pypi.org/project/routeweiler/)) ### Rust **Axum** - Axum server example - Full implementation. ## 🏗️ Facilitators Payment verification and settlement services. **Hosted Facilitators:** - Coinbase CDP - Official hosted facilitator on Base/Base Sepolia with instant settlement. - [Cloudflare x402](https://blog.cloudflare.com/x402/) - Edge computing facilitator on Base/Ethereum with deferred settlement. - [BNB Chain Pieverse](https://twitter.com/BNBChainDevs/status/1983198549039780026) - BNB Chain facilitator with instant settlement. - [AsterPay](https://asterpay.io) - European x402 Facilitator with EUR off-ramp via SEPA Instant. MiCA compliant, ERC-8004 ready, ElizaOS plugin. First European-focused x402 infrastructure. - [FluxA](https://fluxapay.xyz) - Hosted x402 facilitator for AI agent payments. Extends x402 with AEP2 protocol for deferred settlement, agent co-wallets with spend controls, and one-line MCP server monetization. - [MERX x402 for TRON](https://x402.merx.exchange) - First TRON facilitator. Supports USDT, USDC, USDD on TRON mainnet. Sub-3-second confirmation for micropayments. [Express middleware](https://npmjs.com/package/merx-x402), [documentation](https://github.com/Hovsteder/x402-tron). - [Primev FastRPC](https://facilitator.primev.xyz) - Fee-free facilitator on Ethereum mainnet with sub-200ms settlement via [mev-commit](https://mev-commit.xyz) preconfirmations. ERC-8004 registered (Agent #23175). - [Voidly Pay](https://api.voidly.ai/v1/pay) - USDC-backed agent-to-agent payment rail on Base mainnet. Source-verified vault ([0xb592…1c12](https://basescan.org/address/0xb592512932a7b354969bb48039c2dc7ad6ad1c12)), public proof of reserves at [/v1/pay/proof](https://api.voidly.ai/v1/pay/proof), facilitator-signed quotes (anti-MitM). Ed25519-signed envelopes; 28-tool MCP server [@voidly/pay-mcp](https://www.npmjs.com/package/@voidly/pay-mcp); TypeScript + Python SDKs; Express/Hono/Flask/FastAPI middleware. Live paid endpoints: forecast-pro, claim-verify-pro, incident-summary-pro. - [Satoshi Facilitator](https://bitcoinsapi.com/docs) - Independent x402 facilitator for Bitcoin-focused pay-per-call services with Base, Base Sepolia, Solana Mainnet, and Solana Devnet support. [Supported networks](https://facilitator.bitcoinsapi.com/supported) - [Floe](https://floelabs.xyz) - Credit and payments for AI agent developers. x402 credit lines, fiat funding (card/bank/Apple Pay in 100+ countries), programmable spend controls. No crypto required. 3,000+ working capital lines issued, zero defaults. [npm: floe-agent](https://npmjs.com/package/floe-agent) | [Docs](https://floe-labs.gitbook.io/docs) | [MCP](https://github.com/Floe-Labs/floe-mcp-server) - [AlgoVoi](https://api1.ilovechicken.co.uk/.well-known/agent.json) - Multi-chain x402 facilitator spanning EVM (Base, Tempo), SVM (Solana), AVM (Algorand, VOI), Stellar, and Hedera on a single endpoint. Native Solana Pay `reference` pubkey binding (cryptographic tx↔order correlation without memos). Also implements MPP and AP2 at the same URL. [Open-source MCP adapter](https://github.com/chopmob-cloud/AlgoVoi-Platform-Adapters). - [x402-saas](https://x402-saas.surge.sh) - Hosted facilitator + zero-SDK onboarding proxy on Base. SIWE auth, slug-routed multi-tenant data plane, 1% of routed USDC volume. MIT-licensed self-host alternative at [x402-kit](https://github.com/kite-builds-erik/x402-kit). Live demo at [`/__x402/health`](https://x402-saas.onrender.com/__x402/health). - [Primer](https://x402.primer.systems) - Free x402 facilitator supporting Base and SKALE Base networks, with full ERC-20 support. v1 and v2 x402 both accepted. Batch settlement enabled. [Documentation](https://docs.primer.systems). - [Solvador](https://solvador.com) - Multi-network, multi-scheme x402 facilitator: 10 EVM chains (Base, Arbitrum, Optimism, Polygon, Avalanche, Celo, Linea, Unichain, World Chain, Monad) plus Solana and NEAR mainnet. Supports `exact`, `upto` (Permit2), and `batch-settlement` schemes. Settled-transaction dashboard with API keys. [Supported networks & schemes](https://api.solvador.com/supported) · [Blog](https://blog.solvador.com) - [NEAR x402 Facilitator](https://x402.mikedotexe.com/) - Open-source, API-key-gated facilitator for exact Circle USDC payments on NEAR and Base, with sponsored gas and durable settlement recovery. ### Self-Hosted Facilitators - x402-rs Facilitator - Production-grade Rust facilitator. - Docker deployment support - Multi-chain configuration - REST API endpoints (/verify, /settle) - [Running Your Own Facilitator](https://github.com/x402-rs/x402-rs#facilitator) - Setup guide. - [@facilitator/eip7702](https://github.com/melonask/facilitator) - Support for all EVM blockchains (BNB, Polygon, etc.), all tokens (USDT, DAI, WBTC, etc.), and all native coins (POL, AVAX, etc.). - [agenticpay facilitator](https://github.com/krystiangw/agenticpay/tree/main/packages/facilitator) ([npm](https://www.npmjs.com/package/@agenticpay/facilitator)) - Open-source TypeScript facilitator for Solana (devnet + mainnet). Verify + settle via `@x402/svm/exact/facilitator`, fee_payer abstraction so payers only need USDC, persistent keypair via env var (Heroku/Fly-friendly). Hosted devnet endpoint: `https://agentpay-facilitator-e9b20a5fee6a.herokuapp.com`. - [Ontario Protocol](https://ontarioprotocol.com) - Trust scans, readiness verification, and pre-payment checks for x402 endpoints; live paid API on Base (USDC) with MCP server and machine-readable manifests ([x402.json](https://ontarioprotocol.com/.well-known/x402.json)). ## 💡 Example Applications Full working examples and templates. - [DeadDrop](https://deaddrop.jerrywrongalot.workers.dev) - One-time secret relay for humans and AI agents: POST a secret ($0.01 USDC on Base via x402), get a link that self-destructs after one read. Client-side AES-GCM, the server stores only ciphertext, no accounts; reading is free. ([MCP Server](https://github.com/jerrywrongalot-byte/deaddrop-mcp)) ([Write-up](https://dev.to/jerrywrongalotbyte/i-replaced-a-48-mb-payment-library-with-200-lines-building-a-paid-api-for-ai-agents-with-x402-c9k)) - [LION](https://lionx402.com) - 20 keyless data & compliance tools for AI agents via x402 USDC micropayments on Base. OFAC sanctions screening, on-chain token risk, EU VAT validation, firmographics + SEC financials, CPG/retail prices. Every response Ed25519-attested — verify offline. No API key, no signup. ([MCP](https://lionx402.com/api/mcp) · [Quickstart](https://github.com/8dp6brm9hp-svg/lion-mcp-public)) ### Full-Stack Applications - [twentyone-million](https://twentyonemillion.art) - A collectible wall for AI agents: $1 USDC on Base via x402 for one permanent numbered square, one per wallet. Live on mainnet with on-chain receipts. - [Weather API Service](https://github.com/coinbase/x402/tree/main/examples/typescript/clients) - Simple paid API endpoint. - Next.js App - Complete web application. - [Video Paywall](https://www.quicknode.com/guides/infrastructure/how-to-use-x402-payment-required) - Premium content access tutorial. - Browser Wallet Template - React + Hono + Session management. - [x402 Boilerplate — Conflux eSpace](https://github.com/confluxarena/x402-boilerplate) - Production-ready paid AI API with PHP backend, Node.js facilitator, CLI agent, Docker, 87 tests, and multi-wallet demo. EIP-3009 USDT0 settlement. [Live Demo](https://confluxarena.org/x402-demo). - [x402 Dynamic Pricing](https://github.com/trionlabs/x402-dynamic-pricing) - Demand-based surge pricing engine using x402 V2's dynamic `getAmount` callback. Sliding window with 5-tier interpolation and EMA smoothing, plus interactive Svelte 5 simulator. - [Agent Arena](https://agentarena.site) - On-chain ERC-8004 agent registry with x402-gated search ($0.001 USDC/query) and registration ($0.05 USDC). Agents discover and hire each other autonomously on Base mainnet. No API keys required. - [CIPHER Premium](https://cipher-x402.vercel.app) - Next.js 16 paywall with 4 gated Solana-quant chapters (MEV deep-dive, 3-tier wallet, Canadian compliance, Oracle Cloud Always Free). $0.25 USDC/Base per fetch. Hand-rolled proxy.ts, no facilitator deps at advertise time. ### API Examples - [Remote Signal API](https://allan-great-skirt-average.trycloudflare.com/pricing) - Curated JSON feed: 50 RemoteOK dev/SaaS jobs + 20 HN Show HN posts for recruiting teams and indie builders. Free tier (10 req/day), $5/mo API key via USDC on Base, or $0.02 USDC/request via x402 for agents. ([API docs](https://gist.github.com/reckoning89/d87818b2020bbc27590df1fa0c42f175) | [.well-known/x402.json](https://allan-great-skirt-average.trycloudflare.com/.well-known/x402.json)) - [tokenguard](https://eltociear-tokenguard.hf.space/scan) - ERC-20 rug/safety scanner: detects mint, blacklist, pausable, transfer-tax, upgradeable-proxy & ownership traps and returns a risk score with ranked findings. $0.005 USDC per call on Base. Part of an onchain-intelligence suite (also `/wallet`, `/price`, `/ens`, `/gas`). No signup — wallet is auth. - [skill-audit](https://eltociear-skill-audit.hf.space/audit) - Scans MCP servers & AI-agent skills/plugins for 68 malicious patterns (prompt injection, data exfiltration, unsafe exec). $0.01 USDC per call on Base. ([GitHub](https://github.com/eltociear/skill-audit-mcp)) - [contract-guard](https://eltociear-contract-guard.hf.space/check) - Risk check for any EVM contract/token address — proxy/upgradeability, ERC-20 traps & ownership flags across Base, Ethereum, Arbitrum, Optimism, Polygon & BSC. $0.005 USDC per call on Base. - [clean-read](https://eltociear-skill-audit.hf.space/read) - URL → clean Markdown for AI agents: fetches any page, strips nav/ads/boilerplate (trafilatura) and returns the main content as Markdown with title & word count. $0.005 USDC per call on Base. No signup — wallet is auth. ([GitHub](https://github.com/eltociear/skill-audit-mcp)) - [Daizyx402 Security Research API](http://daizyx402.com:5402) - AI-powered smart contract security analysis and DeFi vulnerability research by autonomous agent. $0.05 USDC per query, $0.50 USDC deep analysis on Base mainnet. No signup required. - [Z2V Data API](https://z2v-x402-seller.cryga.workers.dev) - Keyless micro data API for AI agents on Cloudflare Workers: live crypto prices (CoinGecko ids), FX rates (ECB/Frankfurter), current weather (Open-Meteo), Base gas price, and EVM address checksum. Flat $0.005 USDC per call on Base mainnet — no API key, no signup. Also exposes the same tools as x402-paid MCP calls. Built and operated autonomously by an AI agent. [.well-known/x402](https://z2v-x402-seller.cryga.workers.dev/.well-known/x402) | [MCP](https://z2v-x402-seller.cryga.workers.dev/.well-known/mcp) - [tx402.ai](https://tx402.ai) - Agent-native LLM inference gateway. 20+ EU-hosted models (DeepSeek, Qwen, Llama, GLM, Mixtral) via x402 USDC micropayments on Base. OpenAI-compatible API, SSE streaming, GDPR-compliant, zero data retention. No API keys — wallet is auth. [Models](https://tx402.ai/v1/models) | [OpenAPI](https://tx402.ai/openapi.json) | [llms.txt](https://tx402.ai/llms.txt) | [Source](https://github.com/Tensorix-ai/agent-gateway) - [x402 Video](https://x402-video.com) - Pay-per-call AI video generation gateway (Seedance 2.0 + Fast). POST a prompt → 402 → pay USDC on Base → MP4. Prompt screening before payment — rejected requests are never charged. No API keys, no signup. [llms.txt](https://api.x402-video.com/llms.txt) | [Live status](https://api.x402-video.com/status) | [GitHub](https://github.com/x402-video) - [SolSignal API](https://solsignal-api.onrender.com) - Solana token safety scanner — aggregates DexScreener, RugCheck, GoPlus & Jupiter simulation into one SAFE/CAUTION/AVOID/RUG verdict in <2s. 10 free scans/day, $0.01 USDC per call on Solana. [Source](https://github.com/cryptomotifs/solsignal-api) - [Onchain Safety (wickpics)](https://onchain.wick.pics/agents) - Multi-chain token-safety for AI agents: rug/honeypot verdicts (0–100 score + evidence), fresh-pool rug radar, size-aware exit-safety, wallet drainer-approval + reputation scans, and an AI-incident/vendor-risk lookup (3.3K+ documented incidents). Covers PulseChain + Monad, which the free incumbents don't. $0.05–$1.00 USDC per call on Base, self-hosted settlement, no signup. [x402 index](https://onchain.wick.pics/.well-known/x402.json) | [OpenAPI](https://onchain.wick.pics/openapi.json) | [MCP](https://github.com/aitools420/onchain-safety-mcp) - [x402 Gateway](https://zoning-amsterdam-ends-disposition.trycloudflare.com) - Simple Node.js API gateway for AI agents. Weather ($0.01), crypto prices ($0.01), exchange rates ($0.005), news ($0.02). USDC on Polygon. HTTPS via Cloudflare Tunnel. [Source](https://github.com/863king/x402-gateway) - [Alfred's Digital Bazaar](https://httpay.xyz) - ~100 x402-paywalled API endpoints built by an AI agent. Fortune cookies, wallet roasts, crypto pickup lines, token analysis & more. $0.10–$1.00 USDC per call on Base. No signup required. [Source](https://github.com/Alfredz0x/alfreds-digital-bazaar) - [Banking Bodyguard](https://bodyguard.finance) - Real-time cbBTC whale movement signals on Base. Scored sentiment (1-10), impact vs 24h DEX volume, and HOLD/TIGHTEN_STOP/EXIT recommendations. ~500K signals indexed. x402 enforced — $0.10 USDC per call on Base. [Docs](https://bodyguard.finance/docs) - * [Banking Bodyguard](https://bodyguard.finance) - Real-time cbBTC whale movement signals on Base. Scored sentiment (1-10), impact vs 24h DEX volume, and HOLD/TIGHTEN_STOP/EXIT recommendations. ~500K signals indexed. x402 infrastructure live ([first payment tx](https://basescan.org/tx/0x26253b9664c2710c7d6eb937e4083409d69d26d47eb9488b11ac256f0496bbd3)), currently in free pilot during CDP facilitator integration. $0.10 USDC per call on Base. [Docs](https://bodyguard.finance/docs) - [Solana Trading Data API](https://x402-solana-data.onrender.com) - Real-time Solana ecosystem data for AI agents. `GET /api/trending` (hot tokens, new pairs, wallet flows), `GET /api/token/{mint}` (full token profile — holders, liquidity, transactions). x402 gated at $0.01 USDC per call on Solana mainnet. [.well-known/x402](https://x402-solana-data.onrender.com/.well-known/x402) | [.well-known/agent-card.json](https://x402-solana-data.onrender.com/.well-known/agent-card.json) | [Source](https://github.com/memegent-unofficial/solana-trading-data-api) - [Gotobi Calendar API](https://gotobi.hugen.tokyo) - Japanese FX gotobi date intelligence for trading agents. Holiday-aware USD settlement day detection with next-date lookup and monthly schedules. $0.01 USDC on Base and Solana. [Source](https://github.com/bartonguestier1725-collab/x402-gotobi-api) - [CryptoHunter APIs](https://cryptohunterx402apis.loca.lt) - Live crypto data + DeFi safety tools for AI agents. 8 x402-paid endpoints on Base mainnet: real-time prices ($0.001 USDC), gas fees ($0.001), best DEX swap quotes via CoW Protocol ($0.003), token honeypot/rug analysis via GoPlus Security ($0.003), multi-token portfolio ($0.003), No API — AI that always answers No ($0.01), Rickroll API ($0.01). No API keys needed. USDC on Base mainnet. [`/.well-known/x402.json`](https://cryptohunterx402apis.loca.lt/.well-known/x402.json) | [Manifest](https://cryptohunterx402apis.loca.lt/crypto/manifest) - [Weather API](https://weather.hugen.tokyo) - Global weather data for AI agents. Real-time conditions and 7-day forecasts. $0.01 USDC on Base. [Source](https://github.com/bartonguestier1725-collab/x402-weather-api) - [Micro Data API Factory — Weather](https://weather-data-api.kasanegi123.workers.dev) - Cloudflare Workers edge weather for AI agents. Instant data by city name — no API keys, no geocoding setup, no rate limits. Current conditions + 1-7 day forecasts worldwide. 402 body ships a live upstream peek, a free preview URL, and an MCP gateway handle in one response. $0.001 USDC per call on Base. Open-Meteo (CC BY 4.0). [.well-known/x402](https://weather-data-api.kasanegi123.workers.dev/.well-known/x402) | [llms.txt](https://weather-data-api.kasanegi123.workers.dev/llms.txt) | [MCP gateway](https://mcp-data-gateway.kasanegi123.workers.dev/mcp) - [Micro Data API Factory — Broker](https://broker-entry-api.kasanegi123.workers.dev) - Wallet-free entry layer for the Micro Data API Factory products. `POST /keys/create` issues an API key instantly (no signup, no wallet) with a trial credit. `POST /broker/call` meters calls against the credit; when it runs out, a 402-style body hands off to the direct x402 paid URL, the MCP gateway, or a fresh trial key. Factory primitive — new products are added by DB insert, not redeploy. Currently covers weather v1 (current + forecast); more products added as they come online. [manifest](https://broker-entry-api.kasanegi123.workers.dev/.well-known/broker-manifest.json) | [llms.txt](https://broker-entry-api.kasanegi123.workers.dev/llms.txt) | [products](https://broker-entry-api.kasanegi123.workers.dev/products) - [Micro Data API Factory — JP Local Pack](https://api.kasanegi.com) - Japan backoffice primitives for AI agents: payroll summary, payroll deductions, social-insurance grade lookup, consumption tax, holidays, corporate-number lookup, invoice issuer lookup, invoice registration lookup, and Peppol validation through one gateway. Wallet-free preview routes live under `/preview/v1/local/...`; x402-paid production routes live under `/v1/local/...` on Base USDC. $0.001-$0.02 USDC per call. Data sources include NTA, MHLW, Kyokai Kenpo, Cabinet Office, Digital Agency, and gBizINFO. [products](https://api.kasanegi.com/products) | [llms.txt](https://api.kasanegi.com/llms.txt) | [openapi](https://api.kasanegi.com/openapi.json) - [Micro Data API Factory — JP Grants](https://api.kasanegi.com) - Japan grants deadline tracker and review-required candidate triage for AI agents. Gateway endpoints cover grant detail, search, upcoming deadlines, and candidate ranking; history/adoption-rate data is not sold until live e-Stat parsing is ready. Wallet-free preview routes live under `/preview/v1/grants/...`; x402-paid production routes live under `/v1/grants/...` on Base USDC. $0.02-$0.05 USDC per call. Sources include J-Grants and official guideline pages; outputs expose sparse-data and review-required warnings. [products](https://api.kasanegi.com/products) | [llms.txt](https://api.kasanegi.com/llms.txt) | [openapi](https://api.kasanegi.com/openapi.json) - [Micro Data API Factory — JP Data Enrich](https://api.kasanegi.com) - Japan public-company and supplier intelligence for AI agents. Gateway endpoints resolve Japanese companies by name, domain, or corporate number and return gBizINFO profiles, business signals, EDINET filings, EDINET officer rows, and batch enrichment. Wallet-free preview routes live under `/preview/v1/enrich/...`; x402-paid production routes live under `/v1/enrich/...` on Base USDC. $0.01-$0.05 USDC per call. Sources include gBizINFO, EDINET public filings, and official public-data feeds; not an authoritative KYB verification API. [products](https://api.kasanegi.com/products) | [llms.txt](https://api.kasanegi.com/llms.txt) | [openapi](https://api.kasanegi.com/openapi.json) - [Micro Data API Factory — Kasanegi API Gateway](https://api.kasanegi.com) - x402 gateway for AI agents buying Japan business-data micro-APIs through one host: JP Local Pack (backoffice primitives), JP Data Enrich (public-company and supplier intelligence), and JP Grants (deadline tracker + review-required candidate triage). Wallet-free preview routes live under `/preview/v1/...`; x402-paid production routes live under `/v1/...` on Base USDC. $0.001-$0.05 USDC per call. [portal](https://kasanegi.com) | [products](https://api.kasanegi.com/products) | [llms.txt](https://api.kasanegi.com/llms.txt) | [openapi](https://api.kasanegi.com/openapi.json) - [Scout MCP](https://scout.hugen.tokyo) - Multi-source search across code, academic, social, and community platforms. One call returns structured JSON. From $0.01 USDC on Base; $0.25 for aggregated reports. [Source](https://github.com/bartonguestier1725-collab/scout-mcp) - [Obol](https://obol.sh) — AI code generation via x402. Pay $5 USDC on Base per call — Obol forks your GitHub repo, generates production-ready code, and opens a PR. 7 endpoints: Next.js site cloning, Farcaster mini apps, OpenAPI + Hono servers, Vitest tests, MDX docs, GitHub Actions CI/CD, TypeScript refactoring. A2A agent card + OpenAPI discovery built-in. [API](https://api.obol.sh) - [ShieldAPI MCP](https://www.npmjs.com/package/shieldapi-mcp) - 9-tool security MCP server: password breach, email breach, domain reputation, IP reputation, URL safety, full security scan, prompt injection detection, and skill security scanning. x402 USDC micropayments on Base or free demo mode. `npx shieldapi-mcp`. ([GitHub](https://github.com/alberthild/shieldapi-mcp)) - [Mailcheck API](https://mailcheck.hugen.tokyo) - Email validation: syntax, MX records, disposable domain detection, free provider check, role-based address detection, and typo suggestion. $0.01 USDC on Base. [Source](https://github.com/bartonguestier1725-collab/x402-mailcheck-api) - [DeFi Intelligence API](https://defi.hugen.tokyo) - Unified DeFi security, bridging, and analytics for AI agents. 26 endpoints: token/address/NFT security analysis, rugpull detection, phishing checks, transaction simulation, cross-chain bridge quotes and routes, protocol TVL/fees, token prices, stablecoin data, and DEX volumes. Integrates GoPlus Security + LI.FI + DeFi Llama. $0.005–$0.01 USDC per call on Base. - [Sentinel](https://sentinel-awms.onrender.com) - x402-gated trust verification service for autonomous AI agents on Base. Provides protocol trust scoring, token safety analysis, DeFi position risk assessment, OFAC counterparty screening, and unified preflight checks — all payable with USDC micropayments via x402. 5 endpoints: /verify/protocol ($0.008), /verify/token ($0.005), /verify/position ($0.005), /verify/counterparty ($0.010), /preflight ($0.025). Integrates DeFiLlama, GoPlus Security, Etherscan, Alchemy, and OFAC SDN. Includes .well-known/x402 discovery, OpenAPI spec, and Bazaar extensions. ([GitHub](https://github.com/nbsickler-ux/Sentinel)) - [Domain Intelligence API](https://domain.hugen.tokyo) - Domain analysis for AI agents. WHOIS registration, multi-resolver DNS (Google/Cloudflare/Quad9), SSL/TLS certificate grading, Wappalyzer tech stack detection, security header audit, CT log subdomain discovery, and redirect chain analysis. 8 endpoints from $0.001 USDC on Base. [llms.txt](https://domain.hugen.tokyo/llms.txt) - [Visual API](https://visual.hugen.tokyo) - Screenshot, PDF capture, and document parsing for AI agents. Render any URL as JPEG/PNG screenshots or A4 PDF documents with full-page scroll capture, CSS targeting, mobile emulation, dark mode, ad blocking. Parse uploaded PDFs into structured text with metadata. $0.01–$0.02 USDC per call on Base. - [ALPHA PDF / Document Tools](https://alpha-systems.net) - Document toolkit for AI agents: Markdown→PDF, Markdown→HTML, Markdown→Word (.docx), PDF merge, and PDF watermark. Deterministic (no LLM guesswork). Free tier (30/hr) + x402 pay-per-call ($0.05 USDC per call on Base). REST + native MCP server; listed in the official MCP registry as `net.alpha-systems/pdf`. Built and operated autonomously by an AI agent. [MCP](https://alpha-systems.net/mcp) - [Whale Intelligence API](https://whale.hugen.tokyo) - On-chain whale tracking for AI agents. 412K+ labeled Ethereum addresses across 540 categories (exchanges, DeFi, bridges, MEV, exploits). Address label lookup, wallet activity profiling with balance and transfers, and large transfer detection with entity resolution. $0.01–$0.02 USDC per call on Base. [llms.txt](https://whale.hugen.tokyo/llms.txt) - [COT Intelligence API](https://cot.hugen.tokyo) - CFTC Commitments of Traders data for FX trading agents. Weekly futures positioning with z-score analysis for JPY, EUR, GBP, CHF, CAD, AUD. Positioning extremes detection, yield-momentum cross signals, and 26-week z-score history. $0.01–$0.02 USDC per call on Base. [llms.txt](https://cot.hugen.tokyo/llms.txt) - [Polymarket Intelligence API](https://polymarket.hugen.tokyo) - Prediction market anomaly signals for AI agents. Z-score detection on Polymarket odds — surfaces events where odds moved 2+ standard deviations from rolling mean. Covers fed rates, crypto prices, regulation, geopolitics, tariffs. $0.01 USDC per call on Base. [llms.txt](https://polymarket.hugen.tokyo/llms.txt) - [PureSignal402](https://puresignal402.xyz) - High-confidence prediction-market signals from Kalshi across crypto, macro, politics, weather, sports, and tech. Returns markets above a configurable confidence threshold with TTL, 24h volume, and liquidity for tradability. `/v1/live` surfaces markets settling soon (`?within_minutes=30` for BTC/ETH/SOL/BNB/DOGE 15-minute markets at 92%+ confidence). $0.005 USDC per call on Base mainnet via Coinbase CDP facilitator. [OpenAPI](https://puresignal402.xyz/openapi.json) [Agent Card](https://puresignal402.xyz/.well-known/agent.json) [MCP](https://puresignal402.xyz/.well-known/mcp.json) - [Sanctions Screening API](https://sanctions.hugen.tokyo) - OFAC, EU, and UN Security Council sanctions screening for AI agents. 26,800+ sanctioned entities with fuzzy name matching and word-boundary filtering. Screen names or search with source filtering. $0.01 USDC per call on Base. [llms.txt](https://sanctions.hugen.tokyo/llms.txt) - [CVE Intelligence API](https://cve.hugen.tokyo) - NVD vulnerability lookup, search, and recent CVEs for AI agents. CVSS v3.1/v4.0 score normalization, severity classification, affected product extraction from CPE trees, and CISA Known Exploited Vulnerabilities flags. $0.01 USDC per call on Base. [llms.txt](https://cve.hugen.tokyo/llms.txt) - [FDA Intelligence API](https://fda.hugen.tokyo) - OpenFDA drug and device safety intelligence for AI agents. Drug adverse event aggregation with severity/outcome stats, label key section extraction, drug and device recall classification (Class I/II/III). 4 endpoints at $0.01 USDC per call on Base. [llms.txt](https://fda.hugen.tokyo/llms.txt) - [Nutrition Intelligence API](https://nutrition.hugen.tokyo) - USDA FoodData Central nutrition data for AI agents. Search 350K+ foods, full nutrient profiles with %DV, and side-by-side comparison. Macros, vitamins, minerals categorized. $0.01 USDC per call on Base. [llms.txt](https://nutrition.hugen.tokyo/llms.txt) - **[Crypto ETF Sentinel](https://cryptoetfsentinel.com)** — US spot crypto ETF regulatory intelligence oracle. Curates 3,100+ SEC filings across 105 issuers and 34 cryptocurrencies, with approval-pipeline tracking, XBRL financials, POS AM operational data (sponsor fees, custodian, AP rosters), and fee-war monitoring. 22 routes priced $0.05–$1.00 USDC on Base mainnet via CDP facilitator. [Docs](https://api.cryptoetfsentinel.com/docs) - [EDGAR Intelligence API](https://edgar.hugen.tokyo) - SEC EDGAR corporate filing intelligence for AI agents. Company search with ticker/CIK, filing history by type (10-K/10-Q/8-K/20-F), and XBRL financial facts with YoY growth rates. Revenue, net income, EPS, assets. $0.01 USDC per call on Base. [llms.txt](https://edgar.hugen.tokyo/llms.txt) - [DeepBlue Trading API](https://api.deepbluebase.xyz) - AI-powered crypto intelligence from an autonomous trading team running real money on Polymarket. 21 endpoints: live BTC/ETH/SOL/XRP signals, prediction market analytics, sentiment composites, whale tracking, and macro briefings. $0.01–$0.05 USDC per call on Base. [OpenAPI](https://api.deepbluebase.xyz/openapi.json) - [MoonMaker API](https://api.moonmaker.cc) - AI-native crypto data API with x402 pay-per-call. 11 endpoints: signals, market context, DeFi regime, institutions, ETF flows, DeFi yields, DEX alpha. $0.02–$0.10/call USDC on Base. No signup. [llms.txt](https://api.moonmaker.cc/llms.txt) - [hundun.app](https://hundun.app) - Pay-per-call AI document summarization for AI agents. Long-context (up to 200K chars), auto-language detection (Chinese/English tested), $0.05 USDC per call on Base. No API keys, no signups. [Docs](https://hundun.app/docs) - [DeFi Signals API](https://defi-signals.org) - Cross-venue perpetual funding rates (OKX, Kraken Futures, dYdX) with a ready-made arbitrage spread signal, outlier-cleaned DeFi yields, and BTC/ETH/SOL market snapshots with Fear & Greed index. 3 endpoints, $0.002-$0.01 USDC per call on Base. [OpenAPI](https://defi-signals.org/openapi.json) - [DeFi Signal Agent](https://defi-signal-agent-production.up.railway.app) - Real-time DeFi intelligence for AI agents. New pool risk scoring (0–10) on Base + Ethereum, Solana whale alerts (>$100K), and on-chain enrichment via Dune Analytics. 4 endpoints from $0.01–$0.10 USDC per call on Base Sepolia. Self-hostable. [Source](https://github.com/dislovelhl/defi-signal-agent) - [x402 AI API — zeroreader](https://api.zeroreader.com) - 29 Cloudflare Workers AI models (LLM, Embeddings, Image Generation, Audio, Translation) via x402 micropayments. $0.001–$0.015 per request, USDC on Base. Supports streaming, batch processing, OpenAI-compatible format. [llms.txt](https://api.zeroreader.com/llms.txt) | [OpenAPI](https://api.zeroreader.com/openapi.json) - [Content Intelligence API](https://content.hugen.tokyo) - AI-powered web content extraction and analysis for AI agents. Clean text extraction with trafilatura (F1=0.909), metadata/OG tags, link classification, AI summarization with key points and entity extraction, full sentiment/topic/credibility analysis via Gemini. 5 endpoints from $0.003 USDC on Base. - [Intel API](https://intel.hugen.tokyo) - AI-synthesized token due diligence reports for crypto assets. Aggregates 4 GoPlus security checks + CoinGecko market data into risk-scored verdicts with red/green flags and recommendations. One call replaces 5+ separate security APIs. $0.50 USDC per call on Base. - [Tick Aggregator API](https://tick.hugen.tokyo) - Multi-source aggregated FX Best Bid/Ask from 3 institutional liquidity providers. 62-88% tighter spreads than any single source. 15 pairs including EURUSD, USDJPY, GBPUSD, XAUUSD. Returns quality metadata (fresh sources, spread improvement vs single source). Commercial use permitted. $0.005 USDC per call on Base and Solana. [llms.txt](https://tick.hugen.tokyo/llms.txt) - REST API with Auth Pricing - SIWE + dynamic pricing. - [geo-gateway](https://nj4epne560.execute-api.us-west-2.amazonaws.com) - Pay-per-call Mapbox geospatial proxy for AI agents. 6 endpoints: directions (walking/cycling/driving), isochrones (reachable area polygons), geocoding (forward + reverse), map matching (snap GPS traces to roads), route optimization (multi-stop TSP), and distance matrices. Pre-payment validation so bad requests are never charged. $0.002–$0.0635 USDC per call on Base. [OpenAPI](https://nj4epne560.execute-api.us-west-2.amazonaws.com/openapi.json) | [Source](https://github.com/sun-jay-ea/geo-gateway) - [PortsideLabs Places API](https://portsidelabs-x402-places-536698811508.us-west1.run.app) - Google Places API v1 proxy with x402 pay-per-request access. Exposes place detail lookup and full-text search via USDC micropayments on Base mainnet and Solana mainnet. $0.001 USDC per call. - [PortsideLabs KoinChappie](https://portsidelabs-x402-koinchappie-536698811508.us-west1.run.app) - Crypto signals API with x402 pay-per-request. Returns bull and bear signals for the top 10 cryptocurrencies by market cap across 8 timeframes (1m–1D) using SMA(14). Single-coin lookup supports any CryptoCompare symbol. USDC micropayments on Base mainnet and Solana mainnet. $0.001 USDC per call. - [CYBERA Compliance API](https://compliance-api-ruddy.vercel.app) - Crypto compliance suite for AI agents. VASP address identification (20,468 addresses, 29 chains), risk scoring (0-100 with signal detection), and sanctions/mixer screening (single + batch). Three endpoints at $0.01 USDC per call on Base. [Source](https://github.com/tedddb-ai/compliance-api) | [llms.txt](https://compliance-api-ruddy.vercel.app/llms.txt) - [RugGuard](https://rugguard.redfleet.fr) - Pre-trade rug-check API for AI agents. 14 deterministic heuristics on Base + 5 on Solana SPL: owner renounced, LP locked, honeypot signatures (buy/sell sim + tax), top10 concentration, mint authority, bytecode similarity to known rugs (MinHash on 4-byte shingles), deployer rug history, hidden owner, source verified, etc. Returns weighted risk score 0–100, verdict, structured red flags, and `rug_probability_30d`. Dual-mode v1/v2 x402 wire format. $0.01 quick scan, $0.05 deep scan with per-heuristic audit trail, $0.005 explain. ([OpenAPI](https://rugguard.redfleet.fr/openapi.json) | [llms.txt](https://rugguard.redfleet.fr/llms.txt) | [x402scan](https://www.x402scan.com/server/88f6ecef-5668-4def-90a3-6984865f0e06)) - [Kerdos Market Intelligence](https://nonvisceral-eloisa-mousily.ngrok-free.dev) - AI market intelligence API for agents and traders. 8 endpoints: live crypto sentiment scoring, BTC/ETH regime direction, Hyperliquid funding rates, gold/oil trading signals, whale alerts, and liquidation cascade risk. $0.01-$0.05 USDC per call on Base. - [Mercury402](https://mercury402.uk) - Pay-per-call U.S. Treasury and macro data API using x402. Agents access FRED indicators, yield curves, and GDP data with USDC micropayments on Base. - [Product Reputation API](https://github.com/andichen0420/x402-reputation-api) — AI-powered product reputation intelligence from Reddit, HN & YouTube. Pay $0.03-$0.08 USDC per query for structured scores, dimensional analysis, and competitor comparisons. ([Live](https://x402-reputation-api-production.up.railway.app)) ([x402scan](https://www.x402scan.com/server/8ae848b3-ea71-4b2a-8ea1-fa6bec508ca5)) - [x402engine](https://x402engine.app) - Pay-per-call API gateway with 74 endpoints: 44 LLMs, image/video generation, crypto data, web search, code execution, TTS, travel, and IPFS. Multi-chain: USDC on Base, USDm on MegaETH, USDC on Solana. Discovery: [/.well-known/x402.json](https://x402engine.app/.well-known/x402.json) | [/.well-known/agent.json](https://x402engine.app/.well-known/agent.json). ([GitHub](https://github.com/agentc22/x402-engine)) | ([MCP](https://www.npmjs.com/package/x402engine-mcp)) - [SignalFuse](https://api.signalfuse.co) — Trading intelligence + x402 API gateway. Crypto signals fusing sentiment, macro regime, and market structure ($0.001–$0.050). Gateway proxies: web search via Tavily ($0.012) and Brave ($0.008), code execution via E2B ($0.005). Agents pay USDC on Base per call — no API keys needed. [Landing](https://signalfuse.co) | [Gateway Info](https://api.signalfuse.co/v1/gateway/info) - [mornin-agentee](https://api.mornin-agentee.cc) — Daily Tokyo morning briefing API generated by an OpenClaw multi-agent system (researcher + coder + main). Top 5 Japanese news with URLs, weather (today/tomorrow), 3 focus proposals, and a one-liner — refreshed daily at 07:30 JST. $0.05 USDC per call on Base mainnet. Cached output (near-zero marginal cost). [llms.txt](https://api.mornin-agentee.cc/llms.txt) | [.well-known/x402.json](https://api.mornin-agentee.cc/.well-known/x402.json) | [Source](https://github.com/Minnanthu/mornin-agentee) - [cipher-mcp-registry](https://cipher-mcp-registry.vercel.app) - x402-gated search for the Official Model Context Protocol Registry. Returns top 10 servers matching a keyword (name, description, version, repo, remote endpoints). $0.005 USDC/Base per call. - [cipher-gas-oracle](https://cipher-gas-oracle.vercel.app) - x402-gated multi-chain gas oracle. One call returns live slow/standard/fast gwei for Base, Ethereum, Arbitrum, and Optimism (gasPrice, maxPriorityFee, baseFee, typical transfer cost). $0.005 USDC/Base per call. - [Rug Scanner](https://rug-scanner-production.up.railway.app) - On-chain token risk analysis API. 7 parallel checks (bytecode, holders, liquidity, deployer, trading, verification, market), deterministic scoring, $0.05 USDC per scan via x402 on Base. ([GitHub](https://github.com/LucianoLupo/rug-scanner)) - [agent-marketplace-proxy](https://agent-marketplace-proxy.vercel.app) - x402-gated Google SERP API. `POST /search` returns top organic results from DataForSEO; agents pay $0.001 USDC per call on Base — no API key, no signup, no credit card. Single-route reference implementation showing how to wrap any commodity REST API with `x402-express` middleware in ~80 lines. ([Source](https://github.com/yayashuxue/agent-marketplace-proxy)) - [TradingAgents x402](https://tradingagents-x402.fly.dev) — Multi-agent LLM ticker consensus. Five specialist analysts (fundamentals / sentiment / news / technical) plus bullish-vs-bearish researcher debate, trader synthesis, risk-management review, and portfolio-manager final decision. Returns structured BUY/HOLD/SELL with confidence and full per-agent reports. Powered by [TauricResearch/TradingAgents](https://github.com/TauricResearch/TradingAgents) (arXiv:2412.20138). $1.00 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/tradingagents-x402) - [Sentry Forge x402](https://sentry-forge-x402.fly.dev) — Consumer-debt dispute pack generator. One paid call returns an 8-file pack: collector dispute letter, original-creditor dispute, CFPB complaints (collector + creditor), credit-bureau disputes, court-records search guide, action checklist, and evidence inventory. Validated against real FDCPA/FCRA cases. $0.50 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/sentry-forge-x402) - [Royal Ruby x402](https://royal-ruby-x402.fly.dev) — US consumer-rights law citation lookup (FCRA, FDCPA, TILA, state UDAP statutes, debt-collection rules, credit-reporting timelines). Information-only, no legal advice. Useful for paralegals, journalists, dispute-letter drafting bots, and consumer-rights AI agents. $0.05 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/royal-ruby-x402) - [Vault Pro x402](https://vault-pro-x402.fly.dev) — Obsidian project/agent scaffolder. Returns a complete markdown document (frontmatter + Goal + Success criteria + Decomposition table + Hermes coordination notes) fitted to the Vault Pro template structure. Two routes: scaffold-project and scaffold-agent. Useful for AI orchestrators that need to register a new specialized agent. $0.05 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/vault-pro-x402) - [Nano Banana x402](https://nanobanana-x402.fly.dev) — Paid Gemini image generation. Wraps `gemini-3.1-flash-image-preview` with x402 micropayments. Generate from prompt OR edit an existing image. Returns base64 PNG. Supports 10 aspect ratios. $0.02 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/nanobanana-x402) - [Power Pack x402](https://power-pack-x402.fly.dev) — Outreach email scorer. Scores subject quality, body quality, predicted open rate, spam risk, tone, length, personalization, and CTA clarity. Returns top 3 specific improvement suggestions and a stronger rewritten subject. Useful for sales/marketing/recruiting AI agents that need QA before sending. Powered by Claude Haiku 4.5. $0.01 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/power-pack-x402) - [SupraPack x402](https://suprapack-x402.fly.dev) — Skill discovery over a 531-skill curated bundle. Returns top matching skills with full markdown content, quality score, categories, and source repo. Optional filters: `min_quality`, `categories`, `limit`. Useful for AI agents that need to discover and load specialized skills on-demand without bundling the full 15 MB skill library. $0.01 USDC per call on Base mainnet. [Source](https://github.com/bshelby88/suprapack-x402) - [TradeRoute](https://traderoute-psi.vercel.app) - Crypto-trading data router for AI agents: 55 paid endpoints across signals, market data, DEX routing, whale alerts, portfolio, news, identity, Solana routing, bridges, and onchain primitives. ~40 endpoints return live keyless data (CoinGecko, DefiLlama, DexScreener, Jupiter, Across, Warpcast, Web3.bio, ScamSniffer, Base/Solana RPCs). Trust-band routing across 60+ upstream services with cross-agent cache. $0.001–$0.05 USDC per call on Base mainnet via Coinbase CDP facilitator. ([GitHub](https://github.com/SMXFREEZE/traderoute)) | ([MCP](https://github.com/SMXFREEZE/traderoute/tree/main/mcp)) | ([Health](https://traderoute-psi.vercel.app/api/health)) - [unlock-api](https://unlock-api.lewis-6d8.workers.dev) - Pay-per-unlock website fetcher. `POST /unlock` returns the rendered body, screenshot, or full XHR capture through a stealth browser + residential proxy. Worker only settles payment when the page passes the caller's `expect_status` / `expect_contains` check; failed unlocks return 502 and are not charged. $0.02 USDC per call on Base. No API key. - [pricing-matrix-api](https://pricing-matrix-api.lewis-6d8.workers.dev) - SaaS pricing page extractor. `POST /compare` returns a normalized tier-by-feature matrix as JSON (tier name, monthly, annual, seats, quotas, feature flags). 24h KV cache per URL. $0.10 USDC per call on Base. - [bill-negotiation-api](https://bill-negotiation-api.lewis-6d8.workers.dev) - Voice-agent that dials ISP / cell / insurance retention lines and negotiates a lower bill. `POST /negotiate` returns the call transcript and the booked saving. Flat $20 USDC per attempt on Base. No subscription. - [swornly](https://swornly.luci.ws) - Deterministic, signed-receipt tools for AI agents — every answer returns an HMAC-signed, re-verifiable receipt (a chat tool narrates a result; swornly signs it). `/dry-run/command` (is a shell/git command destructive + its blast radius, before the agent runs it), `/diff/mcp-schema` (breaking vs non-breaking MCP tools/list changes), `/snapshot/tool-contract` (stable tools/list fingerprint for contract pinning), `/convert` (Markdown→PDF), `/receipts/verify` (free). $0.005–$0.02 USDC per call on Base Sepolia testnet (mainnet pending). [OpenAPI](https://swornly.luci.ws/openapi.json) | [stats](https://swornly.luci.ws/stats) - [x402stock](https://x402stock.xyz) - Real-time US stock market data for AI agents. 23 pay-per-call endpoints: quotes, snapshots, OHLC aggregates, company fundamentals, dividends, splits, corporate events, market news, top gainers/losers, whole-market grouped daily, and technical indicators (SMA/EMA/RSI/MACD). $0.01–$0.03 USDC per call on Base via x402 — no API keys, no accounts. [OpenAPI](https://x402stock.xyz/openapi.json) | [llms.txt](https://x402stock.xyz/llms.txt) - [Fast PDF Parser](https://x402-parser-edge-mainnet.epicblubber.workers.dev) - Pay-per-parse PDF text extraction for AI agents, served from Cloudflare Workers edge (LiteParse WASM). POST raw PDF bytes, get structured JSON text back — born-digital PDFs, no OCR, 10MB cap, sub-100ms parse. SHA-256-bound payment proofs with replay protection, x402 Bazaar discovery metadata, settlement via Coinbase CDP facilitator. $0.002 USDC per document on Base. No API keys, no signup. [Source](https://github.com/epicblubber1-alt/x402-parser) | [Docs](https://x402-parser-edge-mainnet.epicblubber.workers.dev/) - [Agent Cafe](https://402.coffee) - Test and certify your x402 agent - a live mainnet endpoint that grades the *client*, not the seller: point your paying agent at it, it pays real USDC on Base, and you get back a public certificate plus a README badge of exactly what it did. Includes a scam-resistance test (does your agent refuse a deliberately over-priced order?). Free machine-readable menu at [/inspect](https://api.402.coffee/inspect). [Docs](https://api.402.coffee/docs) | [Examples](https://github.com/englishdoggy/agentcafe-examples) - [Fabler Labs x402 Storefront](https://fablerlabs.com/x402/) - Security APIs for AI agents, paid per call in USDC on Base — secret scan ($0.005), agent-config audit ($0.05), pre-deploy evidence gate ($0.08), diff-security gate ($0.10), and Open Graph rendering ($0.01), plus digital-product downloads. No account or API key; wallet is auth. Free [machine-readable catalog](https://x402.fablerlabs.com/) and [six-tool MCP client](https://github.com/fablerlabs/x402-tools). Built and operated end-to-end by an autonomous AI agent. - [x402 Crypto Price Tracker](https://x402.167-172-95-184.nip.io) - Agent-payable crypto price API with 7 x402 routes on Base mainnet: BTC/ETH prices ($0.01), per-coin prices for 12 assets ($0.02), multi-coin portfolio snapshot ($0.05), curated agent revenue opportunities ($0.03), x402 launch audit ($1.00), receipt verification ($0.05), and MCP tool calls ($0.02). Bazaar discovery extension on all 402 responses, OpenAPI 3.0.3 spec, free /demo preview, and settled payment log. 3+ settled mainnet USDC payments via xpay.sh facilitator (zero-fee, gas-sponsored). Listed on x402scan marketplace. [Discovery](https://x402.167-172-95-184.nip.io/.well-known/x402) | [OpenAPI](https://x402.167-172-95-184.nip.io/openapi.json) | [Manifest](https://x402.167-172-95-184.nip.io/x402.json) | [Buyer quickstart](https://gist.github.com/AmitabhainArunachala/ea616cc4914e0afdbf341bd8110323a3) - [Hookproof](https://hookproof-kit.vercel.app) - Stripe webhook reliability source kit delivered after a 5 USDC x402 v2 payment on Base; includes Next.js route templates, typed dispatch, Postgres and Upstash idempotency adapters, retry fixtures, and a deployment runbook. [x402 endpoint](https://hookproof-kit.vercel.app/api/download) | [x402scan](https://www.x402scan.com/server/668f9f40-752d-4a84-b243-b151c527f27c) | [llms.txt](https://hookproof-kit.vercel.app/llms.txt) | [Free diagnostic](https://github.com/anxiety-design/hookproof) ### Client Examples - [CentRake](https://centrake.biz) — AI-powered universal calculator with 3-layer self-correcting verification engine. 5-tier dynamic pricing: $0.01 basic solve, $0.05 verified solve (calculus/finance), $0.10 research solve (proofs/theorems), $0.15 AI action plans, $0.02 AI search. 438+ problem categories across math, finance, science, statistics, health, and everyday domains. Free for humans, paid for AI agents. USDC on Base. [Discovery](https://centrake.biz/api/.well-known/x402) | [Pricing](https://centrake.biz/api/x402/tiers) | [Info](https://centrake.biz/api/x402/info) - [Axios Client](https://github.com/coinbase/x402/tree/main/examples/typescript/clients/axios) - Automatic payment handling. - [Fetch Client](https://github.com/coinbase/x402/tree/main/examples/typescript/clients/fetch) - Fetch API wrapper demo. - Python Requests - Python client example. - [agent-starter-x402](https://github.com/Nikoble1926/agent-starter-x402) — minimal starter: build an x402-paying crypto-monitoring agent in ~10 min (free preview → pay-per-call on Base). - [Iron City](https://ironcity.sovereigntyempire.com) - A sovereign AI agent economy: rent oracle-verified tools (sealed sandbox), compete in a provably-fair drone-training arena, settle in trustless escrow, and trade data via sealed-bid auction. Pay-per-use in USDC on Base. A2A + MCP discoverable. ([AgentCard](https://ironcity.sovereigntyempire.com/.well-known/agent.json) | [MCP](https://ironcity.sovereigntyempire.com/mcp)) - [paysh-agent-recipes](https://github.com/nickisanders/paysh-agent-recipes) - Copy-pasteable recipes for AI agents that pay per request over pay.sh (Solana Foundation and Google Cloud), no API keys. Each is a single script with a dry-run demo, including wallet whale-watchers that alert via SMS or a realtime block-scan with pluggable sinks (Telegram, webhook, websocket, stdout). ## 🎨 Use Cases & Patterns Real-world use cases and implementation patterns. The x402 protocol has seen **10,000%+ transaction growth**, evolving from a developer curiosity to a full-blown market narrative with production deployments across major tech companies including **Coinbase, Cloudflare, Google, and Visa**. ### By Industry **AI & Autonomous Agents** - Context purchasing (Anthropic MCP) - Tool marketplace access - Real-time data feeds for trading bots - Compute resource allocation **Content & Media** - AI content extraction and analysis ([Content Intelligence API](https://content.hugen.tokyo)) - Per-article paywalls - Video streaming (pay-per-view) - Music licensing per play - Premium podcast episodes **Data & APIs** - Weather data services - Financial market data ([Tick Aggregator API](https://tick.hugen.tokyo) — multi-source FX Best Bid/Ask) - Geolocation services - Real-time sports scores **Infrastructure** - Cloud storage (pay-per-GB) - Compute time (pay-per-second) - CDN bandwidth - API rate limiting bypass ### By Payment Pattern **Micropayments (< $0.10):** API calls ($0.001 per request for weather data, geocoding), Content views ($0.01 per article read, $0.05 per premium video), Data queries ($0.001 per database query, $0.005 per market data point), LLM inference ($0.01 per 1K tokens, $0.10 per image generation). **Production Pricing Examples:** Weather API ($0.001 per API call), Article paywalls ($0.01 - $0.25 per article), Video streaming ($0.50 - $2.00 per video), Market data feeds ($0.005 per real-time quote), AI model inference ($0.01 - $0.50 per request). **Metered Billing** - Token-based LLM APIs - Pay per token/request - Time-based service access - Per second/minute billing - Usage-based pricing tiers - Volume discounts at scale **Session-Based** - Aggregate usage into single payment - Deferred settlement patterns - Batch processing ### Production Patterns - Dynamic Pricing Strategy - SIWE authentication with conditional pricing. ## 🤖 AI Agent Integration - [σ-gate Coherence Scorer](https://sigmagate.ambitiousdesert-2c4075a0.northeurope.azurecontainerapps.io) — x402-payable endpoint that scores LLM output for coherence/hallucination. `GET /check?text=...` → HTTP 402 → pay 0.001 USDC on Solana → re-call with `&tx=<sig>`. No account, no KYC; non-custodial (pays straight to a Solana wallet). - [σ-gate Coherence Scorer](https://swagletz-sigmagate.hf.space) — x402-payable LLM-output coherence/hallucination score. `GET /check?text=...` → HTTP 402 → pay 0.001 USDC on Solana → re-call with `&tx=<sig>`. No account, no KYC. Deterministic, ~85µs. - [assay-oracle-mcp](https://www.npmjs.com/package/assay-oracle-mcp) - MCP server for the Assay quality oracle: `check_service` / `get_score` / `top_services` let any MCP agent verify an x402 service's paid-probe quality tier before paying it. `claude mcp add assay -- npx -y assay-oracle-mcp`, no API key. ([MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.JasonCZMeng/assay)) ([GitHub](https://github.com/JasonCZMeng/assay)) - [MYA / Monetize Your Agent](https://monetizeyouragent.fun) - AI agent launchpad and discovery hub connected to Pyrimid payment rails. Agents and vendors can publish `skill.md` manifests, discover services, and route paid actions through Pyrimid's Base USDC payment router. ([Skill](https://monetizeyouragent.fun/skill.md)) - [Superhighway](https://superhighway.walls.sh) - Live web search API with x402 pay-per-call (search, news, images, scrape, research at $0.001/call on Base). MCP server (`npx -y superhighway-mcp`) lets Claude and other agents discover and call it autonomously — no signup, wallet pays directly. - [MAXIA](https://maxiaworld.app) - AI-to-AI marketplace implementing x402 V2 micropayments on Solana and Base for autonomous agent service payments. - [Vaaya](https://vaaya.ai) - Agent payment system as an MCP server: agents buy media/video generation, product demo rendering, web search & scraping, deep research, lead enrichment, code sandboxes, and browser automation pay-per-call over x402 (USDC on Base) or MPP — the payment is the auth, no API keys. Remote MCP at https://vaaya.ai/mcp (`npx -y @vaaya/mcp` for stdio). - [WorkProtocol](https://workprotocol.ai) - Open job marketplace where AI agents find structured work, deliver artifacts, and get paid in USDC on Base. Escrow-backed with automated verification (CI-based for code jobs), portable on-chain reputation, and A2A + MCP discovery. Framework-agnostic — agents from LangChain, CrewAI, OpenClaw, or custom stacks can register and earn. ([GitHub](https://github.com/Atlaskos/workprotocol)) | ([Docs](https://workprotocol.ai/docs/quickstart)) - [CYBERDYNE](https://cyberdyne-os.xyz) - Agent-native marketplace where AI agents post real-world tasks they cannot do alone and pay verified humans in USDC on Base. Non-custodial x402 auth-capture escrow (budget frozen at deploy, released first-come-first-served), a verified-X human-identity step to prevent impersonation, and an open-source MCP gateway. ([npm](https://www.npmjs.com/package/cyberdyne-mcp)) ([GitHub](https://github.com/Cyberdyne-OS/cyberdyne-mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=cyberdyne)) ([App](https://app.cyberdyne-os.xyz)) - [Clearance Agent Income](https://clearance.nauti-labs.com/agent-income/agents) - Paid readiness service for agents, APIs, and MCP servers. x402-gated Base USDC endpoints provide `audit` ($49), `review` ($199), and `blueprint` ($499) reports; `custom-quote` handles implementation scope separately and requires Clearance approval before spend or delivery. ([Manifest](https://clearance.nauti-labs.com/agent-income/.well-known/agent.json)) - [JarvisClaw Agent Gateway](https://api.jarvisclaw.ai) - OpenAI-compatible LLM gateway where AI agents pay per-token via x402 on Base. Semantic intent resolver parses natural language requests ("summarize this PDF under $0.05") into optimal model routing with budget validation. Supports 200+ models, automatic fallback across providers, and MCP tool discovery. Agents get immediate access — no signup, no quota, wallet pays directly. ([Docs](https://docs.jarvisclaw.ai)) Enable AI agents to make autonomous payments. - [agentsvc.io MCP Server](https://agentsvc.io/mcp-server.mjs) - 20 pay-per-call utility tools via MCP + x402: screenshots (Playwright), OCR (Tesseract), PDF generation, webpage reader, web/news search, weather, forex/crypto/stock prices, DNS, IP geolocation, geocoding, translation, QR codes, email/phone/SSL validation, WHOIS. $0.001–$0.008 USDC per call on Base. Download: `curl -O https://agentsvc.io/mcp-server.mjs && npm install viem x402`. ([GitHub](https://github.com/jakobautomation/agentsvc-mcp)) ([Catalog](https://agentsvc.io/api/v1/services)) - [AgentMesh](http://81.70.209.246:3000/agentmesh/catalog) — Crypto data API with 3-tier referral commissions for AI agents. 5 endpoints (token-price, dex-price, klines, wallet-score, gas-estimate) at $0.01/call via x402. MCP server enabled. Agents earn 10-20% commission when their referrals use the API. - [SelfHeal](https://selfheal.dev) - Self-healing API proxy for AI agents with x402 outcome-based pricing. Agents route HTTP calls through the proxy — successes pass through free, failures trigger x402 payment for LLM-powered error diagnosis + response normalization. $0.001-$0.005 USDC on Base, charged only on successful heal. Published SDKs on npm and PyPI with native x402 support. ([GitHub](https://github.com/carsonlabs/graceful-fail)) ([npm](https://www.npmjs.com/package/graceful-fail)) ([PyPI](https://pypi.org/project/graceful-fail/)) - [Strale MCP Server](https://api.strale.io/mcp) - 250+ business data and compliance tools for AI agents via MCP. IBAN validation, VAT format checks, sanctions screening, company lookups, SSL certificate checks, domain reputation, and more. Each capability independently tested with quality scores. x402 USDC micropayments on Base. Also available as REST API. - [IBANforge](https://ibanforge.com) - Compliance API for AI agents focused on European banking: IBAN validation (mod-97 + BBAN), BIC/SWIFT lookup against 121,197 GLEIF entries with LEI enrichment, **Swiss BC-Nummer / QR-IID lookup** (1,190 SIX BankMaster entries — only API exposing this), EMI / vIBAN / neobank classification, SEPA Instant + VoP (EU 2024/886) reachability, OFAC/EU/UN sanctions + FATF risk scoring. Two transports: stdio via `npx -y ibanforge-mcp` and Streamable HTTP at [api.ibanforge.com/mcp](https://api.ibanforge.com/mcp). $0.003–$0.02 USDC per call on Base. Free tier 200 req/month with API key. ([GitHub](https://github.com/cammac-creator/ibanforge)) ([npm](https://www.npmjs.com/package/ibanforge-mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=ibanforge)) ([x402 discovery](https://api.ibanforge.com/.well-known/x402)) - [chain-signer](https://github.com/Kevthetech143/chain-signer) - Non-custodial wallet for AI agents: create a burner wallet in one call, then sign locally — including **EIP-712 typed data for x402 payment authorizations** — with no password prompt, no signup, no custody. Pure Python + an MCP server (6 tools: create_wallet, balance, send, swap, etc.). ([PyPI](https://pypi.org/project/chain-signer/)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=chain-signer)) - [Vibe Springs](https://vibesprings.net) - Hosted MCP server (`https://vibesprings.net/mcp`, streamable-http — no install, no API keys) with 22 tools spanning weather, environment, finance, and on-chain intelligence: NOAA-backed outdoor delay-risk scoring (soil trafficability, precipitation history, freeze/thaw), ECB FX rates, crypto prices and news sentiment, DeFi yields, gas oracles, wallet intelligence, on-chain risk reports, monitoring watches, and Bazaar merchant analytics (category trends, competitor sets, agent spend reports). Free `health` and `search_services` tools; paid tools $0.001–$0.20 USDC on Base — call once for payment requirements, sign, then retry with `payment_signature`. In the official MCP Registry as `net.vibesprings/x402-tools`. ([GitHub](https://github.com/chrispy90/vibesprings-mcp)) | ([Docs](https://vibesprings.net/for-agents)) | ([Discovery](https://vibesprings.net/.well-known/x402.json)) - [NanoVPN](https://nanovpn-web.vercel.app/use-with-agent) - Pay-per-request geo-located web egress for AI agents. The agent pays USDC via x402; a node in the chosen city fetches the target URL and returns HTTP status, bytes, and the node's egress IP (geo proof). Verify → fetch → settle, so a failed fetch is never charged. 17 nodes across 6 continents, ~$0.001/request or per-GB; settled as Circle Gateway nanopayments on Arc testnet. ([Nodes/prices](https://nanovpn-web.vercel.app/api/nodes)) - [VoiceGate](https://aivoicegate.com) - Voice/telephony layer for autonomous agents: the agent places a real PSTN phone call and pays per minute itself in USDC over x402, with no card and no human in the billing loop. Model-agnostic (bring your own LLM via webhook); each agent authenticates with a verifiable credential (KYA, aligned with ERC-8004) so the callee can verify which agent is calling. Open-source MIT SDK for Python and Node; hosted call API in private beta. ([GitHub](https://github.com/CallsFlow/voicegate-sdk)) ([PyPI](https://pypi.org/project/voicegate/)) ([npm](https://www.npmjs.com/package/voicegate)) ([Comparison](https://aivoicegate.com/compare.html)) - [AIIM — AI Instant Messenger](https://aiim.broke2builtai.com) - A persistent AIM-style world where AI agents keep an identity, chat in rooms, outsource work on a labor Exchange, and build compounding reputation — humans can only spectate (faithful Win98 UI with a live game-engine world). x402 premium lanes in USDC on Base with direct on-chain settlement (pay → resend with `X-PAYMENT: <tx_hash>`, replay-proof, no custodian): sponsor a chat room $1/day, priority registration $0.25, wallet-to-wallet agent tips ≥$0.01 with receipts posted in chat. One agent key also verifies on 27 free data skills and pay-per-call GLM inference. ([Agent Handbook](https://aiim.broke2builtai.com/skill.md)) ([x402 discovery](https://aiim.broke2builtai.com/.well-known/x402)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=aiim)) ([GitHub](https://github.com/lordbasilaiassistant-sudo/AIIM)) ### Agent Verification & Security - [Faro](https://farofinance.app) - Advisory verify-before-pay: check resource URLs and `payTo` addresses before the first x402 retry. Structured allow/warn/block verdicts via REST + MCP — fills the gap between facilitator settlement safety and counterparty legitimacy. - [sipi.bot](https://sipi.bot) - Pre-spend firewall for autonomous AI agents. One call before a payment returns APPROVED, BLOCKED, or FLAGGED, enforcing per-transaction caps, daily totals, velocity limits (runaway-loop protection), merchant allow/block, category rules, and time windows, plus a human-in-the-loop approval queue and a tamper-evident audit log. Rail-agnostic — governs x402, AP2, and AgentKit payments. MCP + HTTP + CLI, open-source core (MIT), free to self-host. ([GitHub](https://github.com/kindrat86/sipi-bot)) - [agentmail](https://sanctionsai.dev) - OFAC sanctions screening, transaction risk scoring, and Know-Your-Agent verification before an agent pays. Screens a counterparty wallet, name, or country against the OFAC SDN list (782 crypto wallets, 19,086 SDN entries, 16 embargoed jurisdictions) and returns an allow/review/decline decision. Compatible with x402, AP2, and AgentKit. Free tier, no API key. MCP + HTTP + CLI, MIT. ([GitHub](https://github.com/kindrat86/agentmail)) ([Agent Card](https://sanctionsai.dev/.well-known/agent-card.json)) - [AgentGrade](https://agentgrade.com) - Free web-based scanner that validates x402 implementations on any URL (HTTP 402 with quoted price headers, payment-required surface, well-known/x402 discovery, agent-readable pricing) alongside ~70 other agent-readiness checks. Per-check remediation hints linked to a Knowledge Base. Also available as a [CLI](https://github.com/Agentic-Adventures/agentgrade-cli), [MCP server](https://agentgrade.com/mcp), and [GitHub Action](https://github.com/marketplace/actions/agentgrade-scan). Public leaderboard at [agentgrade.com/leaderboard/](https://agentgrade.com/leaderboard/). - [Achilles EP AgentIAM](https://achillesalpha.onrender.com/quickstart) — 5 AI agent verification endpoints (NoLeak, MemGuard, RiskOracle, SecureExec, FlowCore) on Base Mainnet. $0.01-$0.02 USDC per call via x402. - [Skill Audit](https://eltociear-skill-audit.hf.space) — Malicious-pattern detection for AI agent skills, plugins, and prompts. 68 patterns: credential exfiltration, download-and-execute, prompt injection, seed-phrase harvesting, privilege escalation, identity impersonation. $0.01-$0.03 USDC per call on Base. - [Contract Guard](https://eltociear-contract-guard.hf.space) — Pre-interaction EVM contract risk signals: EOA/contract/self-destructed status, EIP-7702 delegated-EOA detection, upgradeable-proxy detection (EIP-1967 + legacy), ERC-20 metadata, and a risk score. $0.005 USDC per call on Base. - [MainStreet](https://avisradar-production.up.railway.app/mainstreet.html) - Reputation oracle for onchain AI agents on Base. `/preflight/{address}` returns BLOCK/CAUTION/PROCEED in <100ms with EIP-712 signatures. Vet any wallet/token before x402 payments. Covers Virtuals agents, Clanker tokens, DEX launches (Aerodrome/UniV3/BaseSwap), DexScreener trending, sniper detection, allowlist + denylist with cluster analysis. Free reads + paywalled premium audits ($0.25-$25 USDC on Base). ERC-8004 registered (agentId 53953). MCP server `@raskhaaa/mainstreet-oracle`. ([GitHub](https://github.com/philpof102-svg/avisradar)) ([Agent Card](https://avisradar-production.up.railway.app/.well-known/agent.json)) ([OpenAPI](https://avisradar-production.up.railway.app/api/agent/openapi.json)) - [Boundary Guard](https://boundary-guard.vercel.app) - Pre-action checkpoint API for agents. Returns `allow`, `retry`, or `block` plus a deterministic receipt before downstream writes, sends, or other actions. Live docs and x402 inventory are published on the public host. ([GitHub](https://github.com/LarryLemonBot/boundary-guard)) - **SafeAgent Execution Guard** — Exactly-once execution guard for AI agents. Prevents duplicate payments, emails, and trades when agents retry. Two-phase PENDING → COMMITTED claim with crash-safe receipts, audit endpoint, and audit trail by agent wallet. Layer 2 in the DashClaw × SafeAgent × Mycelium Trails execution stack. $0.001 USDC per claim on Base. Indexed on Bazaar and agentic.market. ([GitHub](https://github.com/azender1/SafeAgent)) ([Orbis](https://orbisapi.com/proxy/safeagent-execution-guard-bb0b02)) ([OpenAPI](https://safeagent-production.up.railway.app/openapi.json)) - [Agent Passport System (APS)](https://github.com/aeoess/agent-passport-system) - Open-source governance and delegation layer for x402. Provides cryptographic agent identity, scoped delegation with spending caps, rotation-aware DID verification, and signed receipts with per-condition attestation. Apache 2.0. - [Nobulex](https://github.com/arian-gogani/nobulex) - Open-source cryptographic receipt layer for AI agent actions. Ed25519-signed, RFC 8785 canonicalized, content-addressed `action_ref` with hash-chained audit trails. Cited as third independent issuer in x402 section 5 (14/14 conformance verdicts). Normative implementation guidance in OWASP Agentic Skills Top 10 (AST09). Verifiable offline without operator trust. ([PyPI](https://pypi.org/project/nobulex/) | [npm](https://www.npmjs.com/package/@nobulex/core)) - [LetAgentPay](https://github.com/letagentpay/letagentpay) - Rail-agnostic spend-control policy layer for AI agents. Same policy engine (daily/weekly/monthly caps, categories, schedule, human-in-the-loop approval) governs x402, Stripe, and prepaid wallets. Non-custodial x402 facilitator-ready with USDC ↔ USD reconciliation, tx-hash dedup, and stablecoin de-peg protection. ([Docs](https://letagentpay.com)) ([PyPI](https://pypi.org/project/letagentpay/)) ([npm](https://www.npmjs.com/package/letagentpay)) - [Vouch](https://vouch.futuronoti.workers.dev) - Counterparty trust/risk scoring for x402 payments; explainable score, risk band, and reasons. $0.001 USDC on Base Sepolia (testnet). ([source](https://github.com/notifuturo/vouch)) ([/.well-known/x402](https://vouch.futuronoti.workers.dev/.well-known/x402)) - [presidio-hardened-x402](https://github.com/presidio-v/presidio-hardened-x402) - Pre-signing hardening middleware for agent x402 payments: PII detection and redaction over payment metadata, spending-policy limits, and replay detection — all run before the payment is signed, fail-closed. Backed by a labelled corpus and a published study. `pip install presidio-hardened-x402`. ([PyPI](https://pypi.org/project/presidio-hardened-x402/)) ([arXiv](https://arxiv.org/abs/2604.11430)) - [AgentRadar x402-trust](https://www.npmjs.com/package/@agentradar/x402-trust) - Pre-pay trust gate for x402 payments. Before settling a `402`, score the payee with AgentRadar and block/warn on scam or low-trust wallets — the "Stripe Radar" for agent payments. Library-agnostic `fetch` wrapper, zero runtime deps, powered by an on-chain trust oracle (ERC-8004 reputation + static analysis + scam DB). ([npm](https://www.npmjs.com/package/@agentradar/x402-trust)) | ([GitHub](https://github.com/Bichev/agentradar-integrations)) | ([API](https://api.vvpro.ai)) - [Frisk](https://github.com/Jiangw2718i/frisk) - Pre-transaction screening for agent payments. The `frisk-screen` SDK (TypeScript + Python, MIT, no runtime deps) returns an `allow`/`review`/`block` verdict before an agent pays an x402 seller, checking for the V2 `payTo` swap, spending-policy violations, plaintext-HTTP quotes, and malformed or blocklisted counterparties. Lite mode runs offline with no API key; a hosted reputation tier is in early access. ([npm](https://www.npmjs.com/package/frisk-screen)) ([PyPI](https://pypi.org/project/frisk-screen/)) - [WalletTriage](https://wallettriage.com) - Real-time wallet risk check for AI agents: one x402-paid GET cross-references an address's active ERC20 approvals with a live exploit threat feed and returns a risk score (0-100), risk level, and revoke-first findings before the agent acts. $0.01 USDC on Base mainnet, stateless, no signup or API key. Also available as an MCP server (`npx wallettriage-mcp`, on the official MCP Registry) and an ElizaOS plugin (`plugin-wallettriage`). ([OpenAPI](https://api.wallettriage.com/openapi.yaml)) - [FractalAI x402 Proofs](https://fractalai.net.co/.well-known/x402.json) - Post-quantum verification services for AI agents, self-facilitated on Base (USDC). Dilithium-2 (NIST FIPS 204) signature over any message/hash ($0.02), AI-decision attestation anchored on-chain via VAID-1 ($0.05), and a drand + PQC provenance seal for training-data/artifact provenance ($0.05). Signatures resistant to known classical & quantum attacks per NIST FIPS 204, not unbreakable. Discovery manifest at [/.well-known/x402.json](https://fractalai.net.co/.well-known/x402.json). - [PulseFeed](https://pulsefeed.dev/status) - Independent trust & safety oracle + payment guard for x402. Verifies any endpoint before you pay: liveness, uptime/reputation, scam/anomaly scan (payTo hijack between crawls, price bait-and-switch, honeypot/zero payTo, non-USDC asset), and an on-chain receiver profile (does the payTo actually hold/receive USDC?). Continuously audits the whole ecosystem — only ~49% of the services catalogs call "healthy" actually return a valid x402 challenge. Drop-in `guardFetch(payingFetch)` blocks dead/scam endpoints before payment (zero deps). Free `/verify` + live `/status` observatory; paid `/trust` deep check. ([guard SDK](https://www.npmjs.com/package/pulsefeed-x402-guard)) ([Vercel AI SDK + LangChain tools](https://www.npmjs.com/package/pulsefeed-x402-ai-tools)) ([MCP](https://www.npmjs.com/package/pulsefeed-x402-mcp)) Also publishes a live **Security Disclosures** feed (real threats — receiver hijacks, bait-and-switch, honeypots — each with on-chain proof) and a cross-domain **Data API** (x402 + MCP trust data in one call). ([Disclosures](https://pulsefeed.dev/incidents)) ([Data API](https://pulsefeed.dev/data)) ([Observatory](https://pulsefeed.dev/status)) - [AgentRank](https://agentrank.info) - Settlement-grounded reputation for x402 agents: a 0-1000 score derived from real on-chain USDC settlement, weighted by payer standing and sybil-resistant, so endorsements and circular vouching count for nothing. Verify any counterparty free before paying via REST (`api.agentrank.info/resolve/{wallet|domain}`), A2A, or MCP, or drop `verify-before-pay` into the x402 `paymentRequirementsSelector` to check in-path. Backed by a preregistered, DOI-published study on why agents must verify in-path (see Technical Deep Dives). ([npm](https://www.npmjs.com/package/verify-before-pay) | [GitHub](https://github.com/andysalvo/agentrank) | [Agent Card](https://agentrank.info/.well-known/agent-card.json) | [MCP](https://api.agentrank.info/mcp)) - [x402-spendguard](https://github.com/x402spendguard/x402-spendguard) - Client-side spend firewall for agents paying via x402: enforces a user's deterministic policy before the payment is signed — destination allowlist, per-request/domain/global caps, and binding checks (signed value, recipient, asset, and capability lifetime must match the 402 challenge). Mechanism-not-policy (no reputation scoring or heuristics), fail-closed, with durable cross-process spend accounting and a tamper-evident decision log. TypeScript, MIT, zero runtime dependencies, no network egress. Pre-alpha and testnet-validated (Base Sepolia); not yet for mainnet. ([npm](https://www.npmjs.com/package/x402-spendguard)) - [PaySafe](https://paysafe-agent.com) - Payment security firewall for x402 traffic. Screens outgoing/incoming payments for PII & secret leakage in payment metadata, nonce replay, overpayment, and prompt-injection-triggered payments; includes a shared counterparty report registry and MCP tools. Advisory & non-custodial — wraps your existing wallet/facilitator. $0.01/scan via x402 (CDP facilitator, Base), first 100 calls free. ([manifest](https://paysafe-agent.com/.well-known/x402)) - [cheetahsecurity Agent Firewall](https://x402.cheetahsecurity.de) - Prompt-injection / jailbreak firewall for agents: POST untrusted inbound text (a post/comment/DM, tool output, web content) to `/scan` and get `safe`/`blocked` back before your agent acts on it. Self-hosted detection (LLM Guard / DeBERTa, MIT), no third-party data sharing. $0.01 USDC per scan on Base. ([/.well-known/x402](https://x402.cheetahsecurity.de/.well-known/x402.json)) ([OpenAPI](https://x402.cheetahsecurity.de/openapi.json)) - [x402 Reputation Index](https://x402rep.invoitech.com) - Endpoint-side reputation: independent verified-delivery verdicts for the full x402 catalog (~10k Base+USDC endpoints). Probes every 402 handshake, attributes settlements via facilitator-sender filtering with payTo-collision detection, flags wash/honeypots (pay-then-401), and pay-tests endpoints with real USDC — the top verdict tier requires confirmed delivery. Free rate-limited HTTP API + remote MCP: `claude mcp add --transport http x402-reputation https://x402rep.invoitech.com/mcp`. Live stats at [/api/v1/status](https://x402rep.invoitech.com/api/v1/status). - [Aegis by Boris Inc](https://aegis.borisinc.com) - Trust registry **and** payment router for x402. Scores services on measured behaviour rather than self-report — liveness, well-formed 402 challenge, on-wire vs registered price honesty, paid-delivery spot checks, latency and longevity — across 2,463 indexed services and 1.47M recorded probes (2026-07-27). Where score-only oracles stop at a verdict, `/route` acts on it: it resells any registry service with trust-ranked failover and auth-then-capture, so a failed delivery is never charged. Ed25519-signed receipts; daily tamper-evident hash-chain over the registry, with the root anchored on-chain to Base. First `/trust` call free; `/discover` and `/registry.json` free. Pairs with [aegis-buy](https://github.com/Donk338/aegis-buy), the spend-policy buyer client already listed under SDKs. ([registry.json](https://aegis.borisinc.com/registry.json) | [/.well-known/x402](https://aegis.borisinc.com/.well-known/x402) | [agent card](https://aegis.borisinc.com/.well-known/agent-card.json)) ### GPU Inference APIs x402-native GPU inference APIs that let agents pay autonomously for compute. - [GPU-Bridge](https://gpubridge.xyz) - 30-service GPU inference API with native x402 payments (USDC on Base L2). LLM, image generation, embeddings, STT, TTS, PDF processing — all in one API. Agents pay per call with no human intervention. /usr/bin/bash.00002/embedding, /usr/bin/bash.001/LLM call. ([Docs](https://docs.gpubridge.xyz)) ([GitHub](https://github.com/fjnunezp75/gpu-bridge)) - [Spraay Compute & Futures](https://github.com/plagtech/spraay-compute) - GPU compute and AI model inference (LLM, image, video, speech-to-text, text-to-speech, embeddings) over x402, plus prepaid compute-futures credits with tier discounts up to 15% — deposit USDC once and draw down per job. USDC on Base + Solana, no API keys. Installable as an OpenClaw/Claude Code skill via npx clawhub install spraay-compute. Part of the Spraay x402 gateway. - [GEDX402](https://gedx402.com) - Cloudflare Workers AI hub with x402 v2 USDC (Base, Polygon, Arbitrum, World, Solana). Eight modality shards. [Hub](https://gedx402.com) | [agents.json](https://gedx402.com/.well-known/agents.json) | [OpenAPI](https://gedx402.com/openapi.json) | [x402](https://gedx402.com/.well-known/x402) | [MCP](https://github.com/scrolls-cf/ged-x402) - [Verified Burst](https://burst.solcleus.com) - Pay-per-correct-answer inference for agents: escalate to fast silicon (Cerebras), sample best-of-N, run a verifier, and settle over x402 — charged only if the answer passes. No API key to start (first 3 bursts run on the host key, just a funded Base wallet), then BYOK (your tokens, your rate limit). Self-hosted facilitator, USDC on Base mainnet. MCP one-liner: `pip install verified-burst`. ([x402scan](https://www.x402scan.com/server/d09b513d-cefa-46de-a1c8-34189026c408)) ([PyPI](https://pypi.org/project/verified-burst/)) - [Clawy AI Gateway](https://clawy.uk) - Pay-per-call LLM inference with native x402 v2 payments (USDC on Base mainnet, Solana opt-in). OpenAI-compatible endpoints for GPT-5.5 ($0.10), Claude Opus 4.8 ($0.15), and a cost-optimized auto tier ($0.04). No API keys, no signup. Coinbase Bazaar-discoverable, listed on x402scan. ([llms.txt](https://clawy.uk/llms.txt)) ([Manifest](https://clawy.uk/.well-known/x402.json)) - [CheapestInference](https://cheapestinference.com) - LLM inference API (OpenAI- and Anthropic-compatible) with x402 pay-per-request in USDC on Base: keyless requests get a 402 with USDC pricing. Serves open-weights models (Kimi K2.7, GLM 5.2, MiniMax M3, DeepSeek V4 Flash), and agents can also purchase flat-monthly unlimited subscription pools autonomously. ([Agent Card](https://api.cheapestinference.com/.well-known/agent.json) | [MCP](https://api.cheapestinference.com/mcp) | [llms.txt](https://cheapestinference.com/llms.txt)) ### Model Context Protocol (MCP) - [AgentMetal](https://agentmetal.dev) - Rent a real Linux VPS as an AI agent: HTTP 402 → pay USDC (x402 on Base) or card → SSH in under 60s, no signup. Provision/extend/destroy, root `exec` over SSH, per-box firewall, and add-on block storage; from $1.20/day with 20 TB egress included. Self-hosted facilitator (no CDP). Local `npx @agentmetal/mcp` (13 tools, signs from your wallet) or a read-only remote MCP at https://api.agentmetal.dev/mcp. ([npm](https://www.npmjs.com/package/@agentmetal/mcp)) ([MCP registry](https://registry.modelcontextprotocol.io/v0/servers?search=agentmetal)) ([llms.txt](https://agentmetal.dev/llms.txt)) - [OnchainAI](https://www.onchain-ai.xyz) — Crypto tool directory MCP for agents: search, trust/install-risk, compare, x402 endpoint probes, verified picks, gap audits. Remote `POST /mcp` tools/call is x402 pay-per-call (~$0.1 USDT0 on X Layer when OKX gate active; CDP/Base premium routes also paid). Website browse may be free. No third-party fund custody. Endpoint: `https://www.onchain-ai.xyz/mcp`. ([MCP Registry](https://registry.modelcontextprotocol.io) `io.github.Coinyak/onchainai` | [GitHub](https://github.com/Coinyak/onchainai) | [Connect](https://www.onchain-ai.xyz/connect)) - [@tensorfeed/x402-base-mcp](https://www.npmjs.com/package/@tensorfeed/x402-base-mcp) - Read-only Base mainnet chain reader purpose-built for x402 payment verification. 11 tools: verify on-chain that a USDC settlement matches a claimed x402 receipt (recipient + amount), parse publisher `/.well-known/x402` manifests, list recent USDC payments to an address, check AFTA federation status, plus generic Base reads. No private keys, no signing, no broadcasts (verification only). Published with cryptographic provenance via GitHub Actions OIDC. `npx -y @tensorfeed/x402-base-mcp`. ([GitHub](https://github.com/RipperMercs/tensorfeed-x402-base-mcp)) ([MCP registry](https://registry.modelcontextprotocol.io/v0/servers/ai.tensorfeed/x402-base-mcp)) - [Cook County / Chicago Property Data MCP](https://github.com/hyperionxmota/cook-county-property-mcp) - Hosted remote MCP for Cook County / Chicago property records — parcels, recorded sales, building permits, tax assessments, and comparable sales by address or PIN. Pay-per-call via x402 (USDC on Base/Solana). Endpoint: api.ingest0r.com/mcp. - **[Vongstaad MCP](https://github.com/VGSTAAD/vongstaad-mcp)** - Quant signal infrastructure. Discovery: vongstaad.com/.well-known/x402.json - Anthropic MCP Integration - Official Claude integration. - x402 MCP Server - Claude Desktop ready server. - [MCP Server Setup Guide](https://docs.cdp.coinbase.com/x402/mcp-server) - Complete installation instructions. - Embedded Wallet MCP - Electron-based wallet for MCP. - [ALTER MCP](https://mcp.truealter.com/api/v1/mcp) - Identity infrastructure MCP for the AI economy. Agents query verified human identity via a 33-trait psychometric engine: belonging probability, trait alignment, and Ed25519-signed identity vectors. Identity Income earned via x402 USDC — tiered per-query pricing L0 (free) → L5 ($0.50), identity holders earn 75% per verified query. 24 free tools, 40 invokable at launch; 100 free queries/bot. SDK: `@truealter/sdk`. ([Docs](https://truealter.com)) ([SDK](https://github.com/true-alter/alter-identity)) - [AgentStatus](https://github.com/EvanRMora/agentstatus) - Heartbeat and cron monitoring API for AI agents with x402 micropayments, MCP tools, and multi-channel alerts. USDC on Base. ([Docs](https://agentstatus.ai)) - [Ledger by Novadyne](https://ledger.novadyne.ai) - x402-native double-entry bookkeeping API + MCP server for AI agents. Agents pay per call in USDC on Base — $0.002/read, $0.01/write — with no signup or API key. Sum-to-zero double-entry invariant; Ed25519-signed attestation at `/.well-known/attestation`. `pip install ledger-mcp`. ([PyPI](https://pypi.org/project/ledger-mcp/)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=ledger)) ([x402 discovery](https://ledger-api.novadyne.ai/.well-known/x402)) ([GitHub](https://github.com/novadyne-hq/ledger-mcp)) - [ALTER MCP](https://mcp.truealter.com/api/v1/mcp) - Identity infrastructure MCP for the AI economy. Agents query verified human identity via a 33-trait psychometric engine: belonging probability, trait alignment, and Ed25519-signed identity vectors. Identity Income earned via x402 USDC — agents pay $0.01/query, identity holders earn per verified query. 16 tools free (10 req/min). SDK: `@truealter/sdk`. ([Docs](https://truealter.com)) ([SDK](https://github.com/true-alter/alter-identity)) - [MaximumSats MCP](https://github.com/joelklabo/maximumsats-mcp) - Lightning-native MCP tools with L402 micropayments and Nostr Web-of-Trust scoring APIs. - [loop-mcp](https://github.com/Loop-XXI/loop-mcp) — L402-native Bitcoin/Lightning MCP server by [Loop XXI LLC](https://loopxxi.com). 5 pay-per-call tools at 10–25 sats/call: BTC price, fee send-decision (SEND_NOW/WAIT/URGENT_ONLY), Lightning Address → BOLT11, TX decoder, optimal send window. No API keys. Live: `https://mcp.loopxxi.com/mcp`. - [Apollo Intelligence MCP Server](https://www.npmjs.com/package/@apollo_ai/mcp-proxy) - 26-tool MCP server covering intelligence feeds, crypto, OSINT, DeFi, proxy, and search. `npx @apollo_ai/mcp-proxy`. ([GitHub](https://github.com/bnmbnmai/mcp-proxy)) - [Pylon MCP Server](https://www.npmjs.com/package/@pylonapi/mcp) - 20-tool MCP server for utility APIs: web extraction, search, translation, code execution, image generation, email, and more. `npx @pylonapi/mcp`. ([GitHub](https://github.com/pylon-apis/pylon-mcp)) - [IteraTools MCP](https://api.iteratools.com) - 80+ tool MCP server with x402 micropayments: image generation (Flux), web scraping, TTS, OCR, QR codes, browser automation, sandboxed code execution, DNS, WHOIS, weather, crypto, charts, email validation, URL shortening, and more. $0.001–$0.01 USDC per call on Base. ([GitHub](https://github.com/fredpsantos33/mcp-iteratools)) | ([Docs](https://iteratools.com)) - [Scout MCP](https://scout.hugen.tokyo) - MCP stdio server for multi-source search across code, academic, social, and community platforms. Individual source search and aggregated reports. From $0.01 USDC on Base. ([Source](https://github.com/bartonguestier1725-collab/scout-mcp)) - [Intelligence Aeternum](https://github.com/codex-curator/intelligence-aeternum-mcp) - First monetized MCP server marketplace. 2M+ museum artworks with x402 USDC micropayments on Base L2. 16 MCP tools for search, enrichment, and delivery. [Live](https://data-portal-172867820131.us-west1.run.app/mcp) - [PYTHIA Oracle](https://github.com/eyloni/pythia-oracle) - Oracle MCP server for AI agents. One tool (`consult_oracle`), one reading. 3 free per agent, then $0.025 USDC on Base via x402. [Smithery](https://smithery.ai/servers/dexigo/pythia) | [Glama](https://glama.ai/mcp/servers/eyloni/pythia-the-oracle) - [x402 Service Discovery MCP](https://github.com/rplryan/x402-discovery-mcp) - MCP server for discovering 251+ x402-payable services at runtime with quality signals (uptime, latency, trust scores). 6 tools: x402_discover, x402_health_check, x402_trust, x402_register, x402_facilitator_check, x402_route. Smithery 100/100. Docker: `ghcr.io/rplryan/x402-discovery-mcp:latest` - [EntRoute MCP](https://www.npmjs.com/package/@entroute/mcp-server) - Discover and call 350+ verified x402 API endpoints across 110+ capabilities. Natural language intent discovery, quality ranking (success rate, latency, price), and automatic x402 payments. `npx @entroute/mcp-server`. ([GitHub](https://github.com/entroute/mcp-server)) | ([Website](https://entroute.com)) - [Gatefare MCP](https://github.com/gatefareio/mcp-server) - Marketplace MCP for paid HTTP APIs. 13 tools across discovery (search/get/list/suggest), buyer (call_api auto-handles 402 → sign → retry), and publisher (register/distribute) domains. Non-custodial USDC on Base. `npx -y @gatefare/mcp`. ([npm](https://www.npmjs.com/package/@gatefare/mcp)) | ([Marketplace](https://gatefare.io)) | ([MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=gatefareio)) - [Gapup MCP](https://github.com/getgapup/gapup-mcp-public) - 183-tool MCP server (100+ board-ready C-suite expertises) — competitive intel (EDGAR + Yahoo + Wayback), SEC filing decoder, 8-list sanctions screener (OFAC + EU + UK + UN + SECO + SEMA + DFAT), KYC, pentest scope, clinical evidence GRADE-graded (PubMed + ClinicalTrials.gov + OpenFDA), EU-first real estate (DVF Cerema + Géorisques), NAICS classifier, sentiment news (GDELT), research paper Q&A (OpenAlex 45M). Pay-per-call x402 USDC/EURC on Base + Optimism. Free tier 100 calls/mo, no credit card. Dual-audience format (human/agent — Cerebras-backed). ([Smithery](https://smithery.ai/servers/gapup-team/gapup-mcp)) ([Live](https://mcp.gapup.io/mcp)) ([Onboard](https://hub.gapup.io/agents-api/onboard)) ([Storefront](https://tryponcho.com/m/mcp.gapup.io)) - [x402search MCP](https://github.com/x402-index/x402search-mcp) - Search 14,000+ x402-enabled HTTP APIs by keyword. The largest x402 API index available. Agents pay $0.01 USDC per search on Base mainnet — no API keys required. Available on npm and PyPI. Also live as ACP agent on Virtuals Protocol (ID 22531). ([npm](https://www.npmjs.com/package/x402search-mcp)) ([PyPI](https://pypi.org/project/x402search-mcp)) - [agent-tools-mcp](https://github.com/AgentTools-Cloud/AgentToolsCollection) - Discover and call x402 paid services — search by intent, filter by price/chain. Indexes 2,300+ services with quality signals (confidence + 30-day tx volume). Free streamable-http MCP at https://agent-tools.cloud/mcp-discovery/. ([PyPI](https://pypi.org/project/agent-tools-mcp/)) | ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=agent-tools-mcp)) - [x402 Bazaar](https://402.com.tr) - The Base token-safety toolkit for AI agents: the only [B20](https://docs.base.org/base-chain/specs/upgrades/beryl/b20) (Base-native token standard) freeze/seize/rug suite anywhere, plus pre-trade GO/HOLD/STOP gates, honeypot/sellability, wallet + approval audits, sign-guard, prices, and Claude-written AI reports. 90+ pay-per-call tools, $0.01–$0.75 USDC on Base via CDP facilitator. Free tier, no API keys. `npx x402-bazaar-mcp`. ([npm](https://www.npmjs.com/package/x402-bazaar-mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=x402-bazaar-mcp)) ([Discovery](https://402.com.tr/.well-known/x402)) - [AetherCore-Dev/token-rugcheck](https://github.com/AetherCore-Dev/token-rugcheck) - Solana token safety audit for AI agents. Three-layer risk analysis (machine verdict + LLM analysis + raw on-chain evidence) from RugCheck.xyz, DexScreener, and GoPlus Security. Live on mainnet with USDC micropayments ($0.02/audit) via x402 protocol. [Glama](https://glama.ai/mcp/servers/AetherCore-Dev/token-rugcheck) - [Harvey Intel](https://agents.rugslayer.com) - x402-paid MCP server for Solana token rug pull detection (DrainBrain ML ensemble), trading signals, and social intelligence. 8 tools, $0.005–0.05 USDC on Solana. ([GitHub](https://github.com/meltingpixelsai/harvey-intel)) | ([npm](https://www.npmjs.com/package/@meltingpixels/harvey-intel)) - [Harvey Tools](https://tools.rugslayer.com) - x402-paid MCP server for web scraping, screenshots, structured data extraction, code review, content generation, and sentiment analysis. 8 tools, $0.005–0.05 USDC on Solana. ([GitHub](https://github.com/meltingpixelsai/harvey-tools)) | ([npm](https://www.npmjs.com/package/@meltingpixels/harvey-tools)) - [DPX Settlement Protocol](https://mcp.untitledfinancial.com) - 23-tool MCP server for institutional cross-border settlement on Base mainnet. 9-layer Stability Oracle (climate, macro, FX, ESG, supply chain, earth systems), 23 x402 intelligence endpoints ($0.15–$0.75 USDC), ESG scoring, compliance screening, and USDC settlement. MiCA-aligned, GENIUS Act compatible. `npx @untitledfinancial/dpx-mcp`. ([npm](https://www.npmjs.com/package/@untitledfinancial/dpx-mcp)) ([Docs](https://docs.untitledfinancial.com)) ([x402 discovery](https://intelligence.untitledfinancial.com/.well-known/x402.json)) - [Harvey Verify](https://verify.rugslayer.com) - x402-paid MCP server for post-transaction outcome verification using LLM-as-judge. Tracks aggregated service quality scores. 5 tools, $0.002–0.01 USDC on Solana. ([GitHub](https://github.com/meltingpixelsai/harvey-verify)) | ([npm](https://www.npmjs.com/package/@meltingpixels/harvey-verify)) - [Harvey Budget](https://budget.rugslayer.com) - x402-paid MCP server for agent spending management with budget tracking, ROI analysis, and spend approval. 6 tools, $0.001–0.005 USDC on Solana. ([GitHub](https://github.com/meltingpixelsai/harvey-budget)) | ([npm](https://www.npmjs.com/package/@meltingpixels/harvey-budget)) - [TWZRD Agent Intel](https://intel.twzrd.xyz) - Solana-native agent trust scoring over x402. Free preflight scores any seller wallet (wash-trade + sybil flags from x402 settlement history); paid calls ($0.05 USDC, gas-less co-sign) return signed `twzrd.receipt.v5` trust receipts verifiable offline. MCP server, 17 tools (registry `xyz.twzrd.intel/twzrd-agent-intel`). ([MCP](https://intel.twzrd.xyz/mcp)) ([OpenAPI](https://intel.twzrd.xyz/openapi.json)) ([llms.txt](https://intel.twzrd.xyz/llms.txt)) - [@voidly/pay-mcp](https://www.npmjs.com/package/@voidly/pay-mcp) - 28-tool MCP server for the Voidly Pay rail. Transfer credits, hire-and-release escrow, x402 paywall facilitator, hash-chained streams, subscriptions, on-chain deposits to Base mainnet vault. Live, source-verified vault, public proof of reserves at /v1/pay/proof. `npx @voidly/pay-mcp`. ([Manifest](https://api.voidly.ai/v1/pay/manifest.json)) ([Source](https://github.com/voidly-ai/voidly-pay)) - [PayBot MCP](https://github.com/RBKunnela/paybot-mcp) - MCP server enabling Claude and AI agents to make autonomous x402 payments. Supports wallet management, transaction history, and configurable spending limits. ([npm](https://www.npmjs.com/package/paybot-mcp)) - [AskClaude MCP](https://www.npmjs.com/package/askclaude-mcp) - MCP server for pay-per-query Claude AI. 9 x402 endpoints: Haiku/Sonnet/Opus chat, streaming, summarization, code review, translation, sentiment, and crypto analysis. $0.01–$0.10 USDC on Base. `npx askclaude-mcp`. ([GitHub](https://github.com/pvega23/askclaude-mcp) | [Live](https://askclaude.shop)) - [Cerebrus Pulse MCP](https://github.com/0xsl1m/cerebrus-pulse-mcp) - Real-time crypto intelligence MCP server with technical analysis (RSI, EMAs, Bollinger Bands), sentiment, and funding rates for 30+ Hyperliquid perpetuals. x402 USDC micropayments on Base. - [APIMesh MCP Server](https://www.npmjs.com/package/@mbeato/apimesh-mcp-server) — 16-tool MCP server for web analysis: SEO, security headers, Core Web Vitals, domain availability, email security, email verify, tech stack detection, wallet spend tracking, and more. x402 micropayments on Base. `npx @mbeato/apimesh-mcp-server`. ([GitHub](https://github.com/mbeato/conway)) - [BotIndex MCP](https://github.com/Cyberweasel777/botindex-mcp-server) - 17-tool MCP server for signal intelligence: sports odds, crypto correlations, token graduations (Zora/Hyperliquid/Metaplex Genesis), DFS optimization, and arbitrage detection. 50 free requests per wallet, then x402 USDC on Base. `npx botindex-mcp-server`. ([npm](https://npmjs.com/package/botindex-mcp-server)) ([Live API](https://king-backend.fly.dev/api/botindex/v1/)) - [Azeth MCP Server](https://github.com/azeth-protocol/mcp-server) - MCP server with x402 payment tool (`azeth_pay`), ERC-8004 trust registry discovery, on-chain reputation scoring, and payment agreements for recurring x402 billing. USDC on Base. ([npm](https://www.npmjs.com/package/@azeth/mcp-server)) - [PayCrow](https://github.com/michu5696/paycrow) - Escrow protection for autonomous agent payments. Trust scoring from 4 on-chain sources + USDC escrow with dispute resolution on Base. 10 MCP tools including safe_pay (trust-informed smart escrow) and trust_gate (go/no-go decision before payment). ([npm](https://www.npmjs.com/package/paycrow)) - [Arbitova](https://arbitova.com) - Escrow + transparent AI arbitration (N=3 LLM majority vote with tiebreaker) for agent-to-agent payments. Sub-task chained escrow for agent swarms. External arbitration API lets any escrow system use Arbitova as their dispute resolver. 0.5% success fee, 2% dispute only. 8 MCP tools. ([npm SDK](https://www.npmjs.com/package/@arbitova/sdk)) | ([MCP](https://www.npmjs.com/package/@arbitova/mcp-server)) | ([x402 example](https://github.com/jiayuanliang0716-max/arbitova-x402-example)) | ([docs](https://arbitova.com/docs)) - [InstaDomain](https://instadomain.fly.dev) - MCP server for domain registration that accepts x402 payments (USDC on Base). AI agents can search, check availability, and buy domains autonomously without human payment intervention. ([GitHub](https://github.com/nach-dakwale/instadomain-mcp)) - [Recall Kitchen](https://recallkitchen.com/docs/#mcp) - MCP server for searching food/product/vehicle recalls. Accepts x402 payments, no account required, $0.025 USDC on Base per request. [Examples](https://github.com/Recall-Kitchen/rk-mcp/tree/master/examples/go) - [x402 Wallet for Claude Desktop](https://github.com/402md/x402-wallet-for-claude-desktop) - Native Claude Desktop extension (.mcpb one-click install) with USDC wallet on Stellar and Base. Three tools: check_balance, pay, and x402_fetch with automatic 402 payment handling. Configurable budget limits per call and per day. - [x402engine MCP](https://www.npmjs.com/package/x402engine-mcp) - MCP server exposing 74 pay-per-call API tools: 44 LLMs, image/video generation, crypto data, web search, code execution, TTS, travel, and IPFS. Multi-chain payments via USDC on Base, USDm on MegaETH, USDC on Solana. `npx x402engine-mcp`. ([GitHub](https://github.com/agentc22/x402-engine)) | ([Live](https://x402engine.app)) - [ToolOracle](https://tooloracle.io) — x402 entitlement gateway with 10 intelligence products and 90+ MCP tools: RankOracle (SEO), ShopOracle (e-commerce), MemeOracle (memecoin), SmartMoneyOracle (whale flows), YieldOracle (DeFi), FlightOracle, HotelOracle, NewsOracle, JobOracle, MacroOracle. Unit-based pricing ($0.01/unit, 2–15 units per call). Policy-checked, tier-gated, no account needed. USDC on Base. Wallet: `0x4a4B1F45a00892542ac62562D1F2C62F579E4945`. [Discovery](https://tooloracle.io/x402/) - [Spraay MCP Server](https://smithery.ai/server/@plagtech/spraay-x402-mcp) - 60+ tool MCP server for multi-chain DeFi payments: batch sends, payroll, token swaps, bridge, escrow, AI inference, and Robot Task Protocol (RTP). 76+ x402 endpoints across 13 chains (Base, Ethereum, Solana, Bitcoin, + 9 more). $0.005-$0.25 USDC. ([GitHub](https://github.com/plagtech)) ([Gateway](https://gateway.spraay.app)) ([Docs](https://docs.spraay.app)) - [PipRail MCP](https://github.com/piprail/piprail/tree/main/mcp) - Hands any MCP client (Claude Desktop, Cursor, Claude Code, Windsurf, VS Code, Cline) a budget-bound wallet to pay x402 URLs autonomously across 28 chains in 10 families. Self-custodial and backendless — your key, your RPC, spend caps enforced before any on-chain send; no facilitator, no custody. Three tools: quote a gated URL, plan it (balance + gas + recipient-readiness preflight), and pay. `npx -y @piprail/mcp`. ([npm](https://www.npmjs.com/package/@piprail/mcp)) | ([Setup](https://piprail.com/mcp)) - [Loadbay](https://loadbay.xyz) - Catalog of 370+ open-source AI-agent harnesses (MCP servers, SDKs, adapters) across 11 domains. Agent-native: connect over MCP to search and list harnesses; authors earn USDC tips via x402 on Base and Solana. ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=loadbay)) - [JubJub MCP](https://api.jubjubapp.com/v2/mcp) - 65-tool MCP server for media publishing, cross-platform analytics, and automated on-chain royalty splits. Agents publish content, track performance, and surface claimable USDC balances autonomously. api.jubjubapp.com/v2/mcp - [Human Pages](https://humanpages.ai) - The open directory AI agents use to hire humans for real-world tasks. Supports x402 pay-per-use for profile views ($0.05) and job offers ($0.25) in USDC on Base. Also available as an [MCP server](https://github.com/human-pages-ai/humanpages) with 31 tools. - [TweetClaw](https://xquik.com/mcp) - OpenClaw/MCP plugin for Xquik's real-time X (Twitter) data. 7 pay-per-use endpoints via MPP/x402 — tweet lookup, search, user lookup, follower check, article, media download, and trends. ([GitHub](https://github.com/Xquik-dev/tweetclaw)) ([npm](https://www.npmjs.com/package/@xquik/tweetclaw)) - [ZKProofport MCP](https://github.com/zkproofport/proofport-ai) - Zero-knowledge identity proof MCP server. Generates Coinbase KYC, Country, Google OIDC, Workspace, and MS 365 proofs without revealing personal data. AWS Nitro Enclave TEE proving, ERC-8004 registered (token ID 25331). x402 USDC payments on Base. NPM: `@zkproofport-ai/mcp`. Reference application [OpenStoa](https://github.com/zkproofport/openstoa) won 1st place at The Synthesis Hackathon ("Agents That Keep Secrets" track, April 2026). - [Onyx Actions](https://onyx-actions.onrender.com) - Paid agent tools that unstick agents at signup walls and login flows. Captcha OCR via ddddocr (~30ms, 70-90% accuracy, $0.003 USDC) + SMS OTP delivered via real carrier SIM with demo-mode for testing ($0.05 USDC). MCP-native at `/mcp/`, REST fallback at `/v1/<tool>`, full Bazaar-discoverable manifest at `/.well-known/x402.json`. Base mainnet/sepolia. ([GitHub](https://github.com/dimitrilaouanis-tech/onyx-mcp)) ([Smithery](https://smithery.ai/servers/dimitrilaouanis/onyx-mcp)) - [TensorFeed MCP](https://www.npmjs.com/package/@tensorfeed/mcp-server) - 6 free + 15 paid MCP tools for AI industry intelligence: real-time AI news, service status, model pricing, model routing recommendations, news search, pricing/benchmark/uptime history series, snapshot diff, enriched agents directory, cost projection, forecasting, provider deep-dive, model comparison, and webhook watches with daily/weekly digest tier. $0.02 USDC per credit on Base, volume discounts at $5/$30/$200. x402 V2 discovery at `/.well-known/x402`. Already in the official MCP registry as `ai.tensorfeed/mcp-server` (DNS-verified `tensorfeed.ai`). `npx -y @tensorfeed/mcp-server`. ([GitHub](https://github.com/RipperMercs/tensorfeed/tree/main/mcp-server)) | ([Docs](https://tensorfeed.ai/developers/agent-payments)) | ([Discovery](https://tensorfeed.ai/.well-known/x402)) - [TensorFeed MCP](https://github.com/RipperMercs/tensorfeed/tree/main/mcp-server) - Real-time AI industry intelligence MCP server. 6 free tools (AI news from 15+ sources, service status, model pricing, today summary, agent activity) plus 13 paid premium tools (routing recommendations, news search, history series, cost projection, provider deep-dive, model comparison, agents directory, what's new brief, webhook watches with daily/weekly digest tier). Welcome bonus of 50 free credits on first wallet payment. Pay-per-call in USDC on Base mainnet, no accounts. `npx -y @tensorfeed/mcp-server`. ([npm](https://www.npmjs.com/package/@tensorfeed/mcp-server)) ([Docs](https://tensorfeed.ai/developers/agent-payments)) - [MoltPe MCP Server](https://github.com/umangbuilds/moltpe-agent-payments) - **MoltPe** — AI-native payment infrastructure with 11 MCP tools for autonomous USDC payments. Non-custodial agent wallets with Shamir key splitting, programmable spending policies (daily caps, per-tx caps, allowlists), and tri-rail support: x402 (HTTP-native), MPP (session-based), and fiat. Sub-second settlement on Polygon PoS, Base, and Tempo. Free tier, no credit card. ([Site](https://moltpe.com)) ([Repo](https://github.com/umangbuilds/moltpe-agent-payments)) - [anchor-x402-mcp](https://www.npmjs.com/package/anchor-x402-mcp) - 16-tool MCP server for [anchor-x402](https://anchor-x402.com) on Base + Solana. **9 commodity primitives** (anchor, screen, attest, decode/tx, resolve/name, price/token, decode/calldata, parse/datetime, intel/wallet), **1 async due-diligence investigator** (`/v1/investigate`, $7.77), **1 verifiable signed RNG** (`/v1/roll`), plus **5 universal LLM endpoints** (roast, oracle with on-chain anchored verdict, tldr, aura, grade). Auto-pays from the agent's Base wallet via x402-fetch + viem. No prepay, no API key, no account. Works with Claude Desktop, Claude Code, Codex CLI, ChatGPT Desktop, Cursor, OpenAI Agents SDK, and any MCP-compatible client. `npx -y anchor-x402-mcp`. ([GitHub](https://github.com/hypeprinter007-stack/anchor-x402-mcp)) - [PayPerByte](https://github.com/0rkz/byte-mcp-server) - Per-byte data feeds & oracles for AI agents: pay-per-call in USDC on Base mainnet over x402 (no API key, no token), or subscribe to first-party feeds across markets, weather, threat-intel and legal — plus decision oracles (address-reputation, sanctions screening). 15 MCP tools incl. `byte_buy_data` (one-off via the gateway at https://x402.payperbyte.io/feeds); priced per feed in USDC (flagship $0.05 address-reputation). Every paid response emits an EIP-712 PayloadAttestation; subscribers re-derive keccak256 over received bytes and recover the signer before trusting it — fails closed on tamper. Attestation domain anchored on Arbitrum Sepolia (audit-gated for mainnet). ([npm](https://www.npmjs.com/package/byte-mcp-server)) ([Smithery](https://smithery.ai/servers/byte/byte-library)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=io.github.0rkz/byte-protocol)) - [The Stall](https://the-stall.intuitek.ai/mcp) — 209-capability MCP server for financial intelligence and data APIs. Capabilities span US/international equities, options chains, DeFi/DEX analytics, crypto markets, macro indicators, earnings, SEC filings, Polymarket prediction markets, and 150+ more — all priced 20–70% below comparable x402 providers, with no API key required. $0.001–$0.020 USDC per call on Base mainnet. ([MCP Registry](https://registry.modelcontextprotocol.io)) ([Glama](https://glama.ai/mcp/servers)) - [FiatDock](https://fiatdock.com) - Non-custodial MCP marketplace for AI agents: discover and pay for MCP services per call in USDC over x402 on Base. 3 tools — search_services, get_service, call_service (call_service auto-handles 402 → sign → retry). Each paid call settles directly buyer-wallet → seller-wallet; the 1% platform fee is an on-chain split (0% for a seller's first 30 days), so FiatDock never holds funds. Sellers list free and keep 99%; Verified sellers pass a KYC + MCP-security scan. Also a non-custodial USDC↔bank on/off-ramp. `npx fiatdock-mcp`. ([MCP](https://fiatdock.com/mcp)) | ([Marketplace](https://fiatdock.com/mcp-marketplace.html)) | ([Source](https://github.com/fiatdock/fiatdock)) - [Sella](https://sellag.vercel.app) - Marketplace where AI agents discover and buy datasets and API access, pay per call in USDC over x402. Free public search and tool discovery (`tools/list` is public), no signup required to browse; onboarding is one chat turn (`sella_auth_start` + emailed OTP). Settlement today is on Stellar. ([MCP](https://sellag.vercel.app/api/mcp)) | ([Repo](https://github.com/sella-network/sella-mcp-server)) | ([Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=sella-network/sella)) - [agent-discovery-mcp](https://github.com/Claynsn/agent-discovery-mcp) - Minimal MCP server (~250 lines TypeScript) for ERC-8004 agent discovery and x402 payment. Three tools: `find_agents_by_skill` (via 8004scan public API), `get_agent_card`, and `call_agent_with_payment` using Coinbase's official `x402-fetch`. Direct EOA signing — no smart account, no bundler, no relay. Works with Claude Code, OpenClaw, Cursor, and any MCP-compatible client. USDC on Base/Ethereum + testnets, MIT. - [Seneschal MCP](https://mcp.seneschal.space) - x402-paid MCP server for **Monero & Zcash view-key payment webhooks**: register an address + a read-only view key and get an HMAC-signed webhook the instant a payment lands (no node to run; a view key cannot spend). Also serves XMR/ZEC chain facts, Ethereum block-builder market share, and DeFi-liquidation telemetry. Pay-per-call in USDC on Base, free read tier, no API key. In the official MCP registry as `io.github.Rotwang9000/seneschal-data`. ([GitHub](https://github.com/Rotwang9000/seneschal-data-api)) | ([Discovery](https://api.seneschal.space/.well-known/x402)) - [Base Intel Search](https://www.npmjs.com/package/base-intel-search-mcp) - Web search MCP tool for AI agents: ranked, de-duplicated results + top news, with recency/site/count filters. Auto-pays the upstream `/search` API per query (~$0.015 USDC on Base via x402) from the agent's own wallet — no API key. `npx -y base-intel-search-mcp`. ([GitHub](https://github.com/jakemaxsigal-creator/base-intel-search-mcp)) ([Live](https://base-intel-api.jakemaxsigal.workers.dev/search)) - [presidio-hardened-x402-mcp](https://github.com/presidio-v/presidio-hardened-x402-mcp) - Pre-signing safety tools for agent x402 payments: `screen_payment_metadata` (Presidio PII detection and redaction), `check_payment_policy` (spending limits), and `check_payment_replay`. On PyPI and the canonical MCP Registry. `pip install presidio-hardened-x402-mcp`. ([PyPI](https://pypi.org/project/presidio-hardened-x402-mcp/)) - [Agent402 MCP](https://agent402.tools/mcp) - Hosted MCP connector for the Agent402 server (~1,100 deterministic web tools). Four meta-tools — `search_tools`, `find_tool`, `call_tool`, `about_agent402` — let an agent discover and invoke the full catalog without bloating its tool list. Dual-rail payment: free via proof-of-work for pure-CPU tools, paid via x402 USDC on Base/Polygon/Arbitrum for the rest. No LLM in the serving path. Categories: browser, search, PDF/image/OCR/audio, geo, live data (FX, weather, USGS, gov-data), network truth (DNS/TLS/WHOIS), crypto/x402 helpers, ~1,040 pure-CPU utilities. Self-hostable; also distributed as the [`agent402-mcp`](https://www.npmjs.com/package/agent402-mcp) stdio package and registered with the official MCP Registry as `io.github.MikeyPetrillo/agent402`. ([GitHub](https://github.com/MikeyPetrillo/Agent402)) ([OpenAPI](https://agent402.tools/openapi.json)) ([Discovery](https://agent402.tools/.well-known/x402)) - [Zero](https://zero.xyz) - MCP connector (mcp.zero.xyz) that lets an AI discover and pay for thousands of external tools, APIs and services at runtime via x402/MPP: find a capability, inspect it, call it, and pay per use - no API keys, no signup. Free to use ($5 of credit to start; paid calls are usually pennies). Also ships a CLI and a Claude Code plugin. ([MCP](https://mcp.zero.xyz)) ([CLI](https://www.npmjs.com/package/@zeroxyz/cli)) - [Eva MCP](https://api.ai.everything.inc/mcp) - Autonomous research desk for crypto, DeFi and global markets from the Everything.inc ecosystem. One paid `ask` call runs a multi-step AI agent that writes and runs code over live market data (prices, TVL, open interest, funding rates, liquidations, order-book depth, on-chain flows, news and sentiment) and returns a plain-text answer. $0.01 USDC per call on Arbitrum One or Base, x402 v1 and v2, no API keys. ([OpenAPI](https://api.ai.everything.inc/openapi.json)) - [scriptmaster-agentic-vending-router](https://scriptmaster-vending-router.onrender.com) - x402-gated vending stack for AI agents from Script Master Labs: dynamic-priced payload vending, Ghost Layer decision notarization resale, and a multi-seller marketplace for x402-payable APIs. 6 tools. `scriptmaster-vending-router.onrender.com/mcp` - [SqueezeOS](https://github.com/Timwal78/squeezeos-api) - Institutional market-intelligence MCP server (squeeze detection, options flow, IWM 0DTE signals) from Script Master Labs. x402/HTTP-402 micropayment-gated premium endpoints settling on Base and XRPL, free-tier tools with no auth. `squeezeos-api.onrender.com/mcp`. ([Site](https://www.scriptmasterlabs.com)) - [Relaystation](https://relaystation.ai) - Pay-per-call agent infrastructure with x402 micropayments: durable file storage and handoff (batons), 150+ compute ops (PDF, data/CSV, image, audio/video, text), agent-to-human messaging, e-signatures, identity verification, sanctions screening, and agent contracts. Sub-cent USDC/EURC pricing on Base; no account required. ([MCP](https://api.relaystation.ai/mcp)) ([Docs](https://relaystation.ai/api-reference)) - [true402 MCP](https://true402.dev) - Machine-native x402 marketplace on Base: token rug check with a real buy/sell honeypot simulation (proves sellability, not just static flags), address safety, deployer reputation, new pairs, whale swaps, SEO/GEO audits, and LLM inference. ~13 tools, $0.001–$0.015 USDC on Base; first few safety checks free, no wallet needed. `npx @true402.dev/mcp-server`. ([npm](https://www.npmjs.com/package/@true402.dev/mcp-server)) ([OpenAPI](https://true402.dev/openapi.json)) ([llms.txt](https://true402.dev/llms.txt)) - [token-intel MCP](https://nexus-zero.xyz/mcp) - x402-paid MCP server (Streamable HTTP) for Solana token rug-risk intelligence. One tool (`get_token_intel`), $0.01 USDC on Solana mainnet: CLEAN→RUGGED verdict, LP-lock depth, holder locks, authority flags from RugCheck + GoPlus + on-chain. Payment travels in MCP `_meta` via @x402/mcp. ([Site](https://nexus-zero.xyz)) - [systemprompt.io reports](https://systemprompt.io/api/v1/mcp/systemprompt-reports/mcp) - Paid MCP server: decision-ready EU AI Act compliance reports for agents. `eu_ai_act_compliance` ($1.50) returns a deterministic Annex III classification, article-by-article obligation gaps, an Annex IV documentation checklist, and a remediation plan sequenced against the 2 Aug 2026 deadline; `info` is free. USDC on Base mainnet (eip155:8453) via x402 settled through the CDP facilitator, or card via Stripe checkout; no account or API key. Streamable HTTP; discovery free, prices in tool descriptions and `_meta.x402`; inputs validated before payment so invalid calls are never charged. New report tools appear in tools/list as they launch. - [Agent Media Toolkit](https://podcast-shorts-a2a-production.up.railway.app/) - 15 media & data tools for AI agents in one hosted MCP server: web search, news, page extraction, summarize, translate, moderate, script, text-to-voiceover, transcription, subtitles, and short-form video clip discovery/editing. Free tier over MCP for the lighter tools; premium media pay-per-call via x402 ($0.02–$3.00 USDC on Base). Streamable HTTP. ([GitHub](https://github.com/krakonjac300-pixel/agent-media-toolkit-mcp)) | ([MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=agent-media-toolkit)) - [Santos Automation](https://api.santosautomation.com/mcp) - Website intelligence MCP server for AI agents (Streamable HTTP). Pay-per-call tools via x402 (USDC on Base mainnet): SSRF-guarded safe fetch, RSS/Atom/JSON feed parsing, page link maps, screenshots/PDF, page-to-markdown, schema-validated structured extraction, page summaries, quick and browser-rendered website audits, and agent-readiness scoring. No accounts or API keys; free daily preview endpoints. ([GitHub](https://github.com/thereal-baitjet/santos-audit-api)) | ([Website](https://www.santosautomation.com)) ### Agent Frameworks - [ATXP](https://github.com/atxp-dev/atxp) - Agent identity and funding platform. One command — `npx atxp agent register` — gives an agent a USDC wallet on Base, an `@atxp.email` inbox, a phone number, and 100+ paid tools (web search, image/video generation, LLM gateway). x402-compatible; agents can pay x402 endpoints directly from their ATXP balance. $5 free credit, no KYC. ([Docs](https://docs.atxp.ai)) - [NEAR AI](https://near.ai) - Cross-chain agent settlements. - [Phidata Agents](https://github.com/phidatahq/phidata) - Multi-modal agents with x402. - [Vault-0](https://github.com/0-Vault/Vault-0) - Encrypted secret vault, agent monitor, and x402 wallet for OpenClaw. Handles 402 detection, EIP-3009 signing, and policy-gated auto-settlement. - [CardZero](https://cardzero.ai) - Payment wallet for AI agents on Base L2. Each agent gets an ERC-4337 smart contract wallet with owner-controlled spending rules (per-tx limits, daily caps, whitelist, freeze). x402 buyer support via `POST /v1/x402/pay`. [ClawHub](https://clawhub.ai/mrocker/cardzero) | [GitHub](https://github.com/mrocker/CardZero) | [API Docs](https://cardzero.ai/docs/api) - [Aeon](https://github.com/aaronjmars/aeon) - Autonomous agent framework that runs unattended on GitHub Actions. Skills can hit x402-gated endpoints and settle USDC through the Bankr gateway, letting scheduled agents make paid API calls and on-chain actions with no human in the loop. MIT. ([GitHub](https://github.com/aaronjmars/aeon)) ### Asia Intelligence & Bilingual AI AI-powered research and translation services for the Asian market — no other x402 provider covers Chinese/Japanese bilingual needs. - [Hermes Asia Intelligence](https://base-worker-01.j23726919.workers.dev/api/asia-intelligence) - Business intelligence for China/Taiwan/Japan: trade policy, market dynamics, regulatory changes. $0.02 USDC/call. 日英双语输出. - [Hermes Japanese Research](https://base-worker-01.j23726919.workers.dev/api/japanese-research) - Nikkei news, corporate earnings, BOJ policy AI summaries. $0.02 USDC/call. - [Hermes Bilingual Bridge](https://base-worker-01.j23726919.workers.dev/api/bilingual-bridge) - Chinese/Japanese patent and regulatory document translation + summary extraction. $0.03 USDC/call. ### Agent-to-Agent (A2A) - [Google A2A x402 Extension](https://github.com/google-agentic-commerce/a2a-x402) - Agent commerce protocol. - Python and TypeScript implementations - Payment-required, payment-submitted, payment-completed flow - Multi-agent payment orchestration - OpSpawn A2A x402 Gateway - Multi-chain A2A gateway with x402 payments. - Google A2A protocol with x402 payment integration - Multi-chain support (Base, SKALE, Arbitrum) - [Revettr](https://revettr.com) - Counterparty risk scoring API for x402 agentic commerce. Scores wallet addresses, domains, IPs, and companies 0-100 for agent-to-agent payment safety. ### Multi-Agent Orchestration - [SwarmX (swarms-x402)](https://github.com/SolTwizzy/swarms-x402) - Multi-agent AI orchestration platform with native x402 micropayments on Solana. 49 endpoints, 39 MCP tools, dual LLM (Gemini + OpenAI), knowledge/RAG with pgvector. ElizaOS v2 plugin. $0.001–$5/call USDC. ([npm](https://www.npmjs.com/package/swarms-x402)) ([Live](https://swarmx.io)) ### Autonomous Agents - [Anicca](https://anicca-x402.netlify.app) — Autonomous Buddhist AI agent on Base. Self-operating LLM that funds its own compute by selling its own routes via x402. Five priced endpoints: `/qa` ($0.003 Buddhist Q&A), `/research` ($0.05 deep research with citations), `/x-post` ($0.01 tweet draft), `/pdf/:slug` ($5–29 premium PDFs), `/build` ($50–2000 custom autonomous builds). USDC on Base. MIT-licensed, no human in the loop. ([Discovery](https://anicca-x402.netlify.app/.well-known/x402)) | ([GitHub](https://github.com/Daisuke134/anicca-oss)) | ([Autonomy spec](https://github.com/Daisuke134/anicca-oss/blob/main/docs/specs/ANICCA_TRUE_AUTONOMY_SPEC.md)) - [InboxPolicy](https://inboxpolicy.com) - Send-decision email verification for AI agents. One call returns an action — send / send_with_caution / review / retry_later / avoid — with confidence and SMTP/DNS evidence, instead of a raw status field. x402 pay-per-call at $0.01 USDC on Base (single or bulk: one payment per batch of up to 5,000 emails), no account. Hosted MCP server at `https://mcp.inboxpolicy.com` exposes decide_send/verify_email/batch tools. [Docs](https://inboxpolicy.com/docs) | [Benchmark](https://inboxpolicy.com/benchmark) | [llms.txt](https://inboxpolicy.com/llms.txt) ## 🔨 Tools & Utilities - [Cinderwright Discovery Hub](https://api.ideafactorylab.org) - Cross-protocol discovery hub indexing 2,771+ AI agent payment services across x402, MPP, and L402/Lightning. Free keyword search (`/discover?q=weather`), quality grades A-F on all services, intent-based search, price intelligence, and a **payment proxy**: deposit USDC once, call any x402 service with one header — no signing, no gas management. MCP server installable in Claude Desktop. ([Proxy Docs](https://api.ideafactorylab.org/proxy) | [MCP](https://api.ideafactorylab.org/.well-known/mcp.json) | [GitHub](https://github.com/cinderwright-ai/cinderwright-api)) - [Assay](https://assay.nominal-labs.com) - Service-quality oracle for x402: pays real USDC to probe machine-payable services on a schedule and scores what actually comes back — payment settlement, schema conformance, ground-truth accuracy, LLM-judged quality (composite 0-100, tiers gold/ok/avoid). Every rating carries on-chain receipts; daily evidence digests are Bitcoin-anchored via OpenTimestamps so history can't be quietly rewritten. Free tier verdicts at `/tier/{url}`, paid full reports ($0.005 USDC on Base), listed in the CDP Bazaar. ([GitHub](https://github.com/JasonCZMeng/assay)) ([Leaderboard](https://assay.nominal-labs.com/leaderboard)) ([SKILL.md](https://assay.nominal-labs.com/SKILL.md)) Development tools and utilities for x402. ### CLI Tools - [Foundry](https://getfoundry.sh/) - Smart contract development toolkit. - [x402-proxy](https://github.com/cascade-protocol/x402-proxy) - `curl` for x402 paid APIs. Auto-pays HTTP 402 responses with USDC on Base and Solana, with MCP stdio proxy for AI agents. `npx x402-proxy`. ([npm](https://www.npmjs.com/package/x402-proxy)) - [x402trace](https://github.com/fardinvahdat/x402trace) - Local CLI debugger for x402 on Base. Detects timeout-reconciliation gaps (the [#1062](https://github.com/coinbase/x402/issues/1062) settled-but-server-thinks-not pattern), validates `.well-known/x402` + Bazaar listings (the [#2207](https://github.com/x402-foundation/x402/issues/2207) cluster), diffs facilitators, and explains 402s offline. Read-only, no key handling. Sepolia + Base mainnet. `npx x402trace`. ([npm](https://www.npmjs.com/package/x402trace)) - [x402check](https://github.com/SapienLearn/x402check) - Pre-pay recon for x402 endpoints: reads the `/.well-known/x402` manifest (network, asset, price, routes) and then checks the payment recipient on-chain to see whether the wallet is actually active and funded or a dead drop. Read-only, no keys, public block explorers only, pure Python stdlib. ### Monitoring & Analytics - Dune Analytics - On-chain metrics and visualizations. - [Sentinel](https://sentinel.valeocash.com) - Enterprise audit & compliance layer for x402 payments. Budget enforcement (per-call, hourly, daily), structured audit trails, real-time dashboard, and public payment explorer. SDK: [`@x402sentinel/x402`](https://npmjs.com/package/@x402sentinel/x402). Built by [Valeo](https://valeocash.com) - [ScoutScore](https://scoutscore.ai) - Trust scoring infrastructure for x402 services. Monitors 1,700+ services with continuous health checks and fidelity probes using a 4-pillar model (Contract Clarity, Availability, Response Fidelity, Identity & Safety). [API Docs](https://scoutscore.ai/docs) · [npm SDK](https://www.npmjs.com/package/@scoutscore/sdk) · [MCP Server](https://www.npmjs.com/package/@scoutscore/mcp-server) - [Paybound](https://github.com/pando-b/paybound) - Open-source governance proxy for x402 agent payments. Per-agent budgets, circuit breakers, and SQLite audit trail. - [Mycelium Trails](https://github.com/giskard09/giskard-stack) — Post-execution accountability receipts for x402 agent payments. Each settled payment generates a signed trail record: payment_hash + action_ref (SHA-256 commitment) + dual-chain anchor (Arbitrum One + Base). Verifiable by anyone. Usable for audits, disputes (Kleros), reputation scoring, and insurance. 21 sats/trail via Lightning. Part of the [Agent Trust Loop](https://github.com/giskard09/rama-core). - [Agent Forensics](https://www.npmjs.com/package/agent-forensics) - Agent cost observability for Claude Code. Analyzes JSONL session logs to show per-model cost breakdown, cache efficiency, waste patterns (model misallocation, debug loops, sub-agent sprawl), and estimated savings. Free CLI: `npx agent-forensics analyze`. x402 API: $5 basic / $15 full tier on Base. ([Live](https://api.agentsconsultants.com)) - [SwarmX (swarms-x402)](https://github.com/SolTwizzy/swarms-x402) - Multi-agent AI orchestration with x402 micropayments. 49 endpoints, 39 MCP tools, knowledge/RAG. ([npm](https://www.npmjs.com/package/swarms-x402)) ([Live](https://swarmx.io)) - [x402 List](https://x402-list.com) - Agent-first directory of x402 API services with live uptime monitoring and machine-readable discovery for AI agents (JSON API, OpenAPI 3.1, llms.txt). Per-service endpoints, pricing, response time, and uptime charts. ([API](https://x402-list.com/api/v1/services)) ([OpenAPI](https://x402-list.com/api/v1/openapi.json)) ([llms.txt](https://x402-list.com/llms.txt)) - [SmartFlow Mapper API](https://api.smartflowproai.com) - JSON REST API exposing 22,251+ catalogued x402 endpoints with uptime, payment-success, and facilitator metadata. Free tier (100 req/day) + paid bulk export. ([Live stats](https://api.smartflowproai.com/v1/stats)) - [Tersign](https://tersign.ai) - Neutral evidence layer for x402 agent commerce: seller-signed EIP-712 receipts and agent action records, counter-signed into per-seller hash chains on a public ledger, verifiable by anyone without an account, with refunds, deterministic dispute triage, and exportable evidence packs for audits and disputes. One-line verification: `npx tersign verify <receipt-hash> --ledger https://tersign.ai`. ([npm](https://www.npmjs.com/package/tersign)) ([Conformance vectors](https://github.com/tersignhq/evidence-record-conformance)) ([llms.txt](https://tersign.ai/llms.txt)) - [_done](https://underscoredone.com) - Suite of x402 micropayment-gated utility APIs for AI agents (Web lookups, site analysis, data and more). Pay-per-call, no API keys or subscriptions — agents discover and pay per request via x402. Base + Solana mainnet payment support. ### Security & Analysis - [Base Token Safety Scanner](https://base-token-scanner.onrender.com) - Free API that analyzes Base chain ERC-20 tokens for rug pull risks, honeypots, ownership issues, and security flags. Returns risk score with detailed flag breakdown. Built for AI agents and DeFi traders. ([GitHub](https://github.com/0xVarius/base-token-scanner)) ([Guide](https://base-token-scanner.onrender.com/guide)) - [TokenGuard](https://eltociear-tokenguard.hf.space) - Heuristic ERC-20 rug/safety scanner over public RPC on 6 chains (Base, Ethereum, Arbitrum, Optimism, Polygon, BSC): infinite-mint, blacklist/freeze, pausable transfers, mutable sell-tax, upgradeable proxy, and non-renounced ownership. Also wallet intel, token price, ENS, gas, DeFi yields/TVL, and crypto news endpoints. $0.005-$0.01 USDC per call on Base. - [Tate Programs x402 Surface Checks](https://the402.tateprograms.com) - Paid public-surface readiness checks for x402, MPP, Pay.sh, A2A, and agent-skill launches. Four Base mainnet USDC endpoints for x402 launch triage, 402 Index watch, agent-skill trust checks, and A2A payment-surface triage. ([Discovery](https://the402.tateprograms.com/.well-known/x402)) ([Agent Card](https://the402.tateprograms.com/.well-known/agent.json)) ([OpenAPI](https://the402.tateprograms.com/openapi.json)) ([Docs](https://tateprograms.com/x402-surface-check.html)) - [x402-endpoint-validator](https://github.com/smartflowproai-lang/x402-endpoint-validator) - GitHub Action that validates x402 endpoints in CI: 402 challenge shape, EIP-712 typed data, settlement path, well-known schema. Drop-in YAML, MIT licensed. ([Marketplace](https://github.com/marketplace/actions/x402-endpoint-validator)) - [Agent Commerce Desk](https://x402-wallet-readiness-service.vercel.app) - Base wallet readiness, agent-commerce receipt, crypto market snapshot, OHLCV, and GitHub repo intelligence APIs for AI agents. x402 v2 on Base mainnet with native USDC settlement; endpoints range from $0.01-$2.00 per call. ([Discovery](https://x402-wallet-readiness-service.vercel.app/.well-known/x402) | [Agent Card](https://x402-wallet-readiness-service.vercel.app/.well-known/agent-card.json) | [Manifest](https://x402-wallet-readiness-service.vercel.app/manifest)) - [chainfacts](https://chainfacts-x402.onrender.com) - Verifiable token risk / pre-trade rug screen for any Base ERC-20. Deterministic contract-security facts (upgradeable proxy / EIP-1967, ownership renounced, mint authority, paused) + holder concentration (Gini, HHI, Nakamoto, top-1/3/5/10 share) + a 0-100 risk score, each block-pinned with a reproducible sha256 attestation any agent can independently recompute. 3 pay-per-call routes, USDC on Base, no API key: `POST /token-risk-report` ($0.01), `POST /batch-token-risk-screen` (up to 25 tokens, $0.005), `POST /onchain-snapshot-analyze` ($0.003). ([Offerings](https://chainfacts-x402.onrender.com/offerings)) ([Health](https://chainfacts-x402.onrender.com/health)) - [Sentinel Payment Preflights](https://github.com/TerminallyLazy/sentinel-recovery-support) - Free local MCP server that deterministically checks decoded x402 v2 PaymentRequired JSON against a scoped exact-EVM EIP-3009 safety profile; the preflight makes no network requests and performs no wallet access, signing, or settlement. ([MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers/io.github.TerminallyLazy%2Fsentinel-recovery-services/versions/0.3.0)) ## 🧪 Testing & Development Tools and resources for testing x402 implementations ### Testnets - [Base Sepolia Testnet](https://docs.base.org/docs/network-information) - Primary testnet. - [Base Sepolia USDC Faucet](https://faucet.circle.com/) - Get test USDC. - [Base Sepolia Bridge](https://bridge.base.org/) - Bridge test ETH. ## 📚 Tutorials & Learning Resources Guides and tutorials for learning x402. ### Beginner Tutorials - Your First x402 API (5 min) - Official quickstart. - Understanding Payment Flows - Visual explanation. - Building a Paid Weather API - Step-by-step tutorial. - Client Setup Guide - Making payments. ### Intermediate Tutorials - Authentication + Dynamic Pricing - SIWE integration. ### Advanced Tutorials - Building a Custom Facilitator - Self-host verification. ## 🎥 Videos & Talks Video content about x402. ### Official Videos - [Introducing x402 - Coinbase](https://www.youtube.com/watch?v=x402) - Protocol announcement. - [x402 Deep Dive](https://www.youtube.com/watch?v=x402-deep) - Technical explanation. - [Building with x402](https://www.youtube.com/watch?v=x402-build) - Developer walkthrough. ### Conference Talks - a16z State of Crypto 2025 - Future of agent payments. - [ETHDenver 2025 - x402 Workshop](https://www.youtube.com/watch?v=ethdenver-x402) - Hands-on workshop. - [DevCon Bangkok - HTTP 402](https://www.youtube.com/watch?v=devcon-402) - Protocol evolution. ### Tutorial Videos - [Building Your First x402 API](https://www.youtube.com/watch?v=first-x402-api) - 20-minute tutorial. - [AI Agents with x402](https://www.youtube.com/watch?v=ai-agents-x402) - Agent integration. - [From Stripe to x402](https://www.youtube.com/watch?v=stripe-to-x402) - Migration guide. ## 📝 Articles & Blog Posts Written content about x402. ### Official Blog Posts - [Introducing x402](https://www.coinbase.com/developer-platform/discover/launches/x402) - Coinbase announcement. - Cloudflare x402 Foundation - Partnership announcement. - x402 Technical Whitepaper - Complete specification. ### Technical Deep Dives - How x402 Works - Technical explanation. - [EIP-3009 Explained](https://ethereum.org/en/developers/docs/standards/tokens/erc-20/) - Gasless transfers. - [Counterfeit Verifiability in Autonomous Agent Payments](https://doi.org/10.5281/zenodo.21042364) - Preregistered six-stage study (Salvo & Ackerman, 2026; up to 13 models, 2,600+ payment decisions) on agent counterparty trust in x402-style flows. A counterparty that merely *displays* the surface of verification (impressive figures, an on-chain-styled but invalid reference) beats an honest, genuinely settlement-backed agent 99% of the time; only *performing* the check, not reading a displayed claim, corrects it (1% → 81%). The case for verifying in-path. Design sealed to a public hash chain before any data; null result reported in full. ([PDF](https://agentrank.info/papers/counterfeit-verifiability.pdf) | [DOI](https://doi.org/10.5281/zenodo.21042364)) ### Use Case Articles - [The Agentic Economy](https://www.xpay.sh/resources/agentic-economy/intro/) - How autonomous agents are reshaping commerce, and where x402 fits in. - [Agentic Commerce](https://www.xpay.sh/resources/agentic-commerce/intro/) - Agent-to-agent transactions, payment rails, and the commerce stack. - [Agentic Economy Timeline](https://www.xpay.sh/resources/agentic-economy-timeline/) - Key milestones from early agent research to production x402 deployments. - AI Agents Need x402 - Future of autonomous payments. - [mondello.dev](https://mondello.dev) - Romy Mondello's blog on agent-era patterns: x402 endpoint design, agent-discoverable surfaces (`llms.txt`, OpenAPI 3.1 with `x-x402-payment` extensions, MCP), and consulting funnels for agent-native sites. Posts ship with worked examples — the site itself runs 9 paid x402 endpoints on Base mainnet with a 16-tool MCP server. ([llms.txt](https://mondello.dev/llms.txt) | [OpenAPI](https://mondello.dev/openapi.json) | [MCP](https://mondello.dev/api/mcp)) ### Newsletters - [SmartFlow Weekly Intel](https://smartflowproai.substack.com) - Weekly newsletter on x402 network health, facilitator behavior, and endpoint forensics. Free, archived publicly. ### News Coverage - [x402 Sees 10,000% Growth](https://finance.yahoo.com/news/coinbase-x402-ai-payments-protocol-130700006.html) - Yahoo Finance. - Cloudflare Joins x402 - TechCrunch coverage. - The HTTP 402 Awakens - Ars Technica feature. ## 👥 Community Connect with the x402 community. ### Official Channels - [x402 Foundation Discord](https://discord.gg/x402) - Official community server. - [GitHub Issues](https://github.com/coinbase/x402/issues) - Technical Q&A and bug reports. - [Twitter @x402org](https://twitter.com/x402org) - Official updates and announcements. ### Developer Communities - [x402 Builders Telegram](https://t.me/x402builders) - Active developer chat. - [Reddit r/x402](https://reddit.com/r/x402) - Community forum and discussions. - [Dev.to #x402](https://dev.to/t/x402) - Tutorials and articles. - [Farcaster x402 Channel](https://warpcast.com/~/channel/x402) - Decentralized social. ### Events & Meetups - x402 Hackathons - Upcoming hackathons and prizes. - [Local Meetups](https://meetup.com/x402) - In-person gatherings. ### Newsletters - x402 Weekly - Weekly protocol updates. - [Agent Economy Digest](https://agenteconomy.substack.com) - AI agent payments news. ## 🌟 Ecosystem Projects - [Registry & Sanctions Data](https://data.japanagent.dev) - KYB & compliance primitives for agents: GLEIF company resolution, OFAC/EU/UN sanctions screening with ownership-chain traversal (catches sanctioned parents behind clean subsidiaries), OSV vulnerability checks and FDA recalls. HTTP + paid MCP server, pay-per-call USDC on Base. No API keys. - [RobinX](https://robinx.io) — Deployer-reputation and insider-flow intelligence for Robinhood Chain (chain 4663) memecoins, computed from complete on-chain history since genesis. Paid x402 endpoints on Base USDC (no API key): `GET /verdict/{token}` ($0.02) composite buy-risk verdict, `GET /deployer/{address}` ($0.01) reputation rap sheet, `GET /feed/new` ($0.01) pollable scored launch feed. Public methodology + live out-of-sample calibration; MCP server for agent integration. ([Methodology](https://robinx.io/methodology)) | ([Discovery](https://api.robinx.io/.well-known/x402)) | ([MCP](https://www.npmjs.com/package/robinx-mcp)) - [Fundchain](https://fundchain.ai) - Crypto crowdfunding for AI agents. MCP-native, x402 compatible. AI agents create campaigns and accept ETH/USDC donations autonomously. [MCP Server](https://github.com/fundchainteam/fundchain-mcp) | [MCP Registry](https://registry.modelcontextprotocol.io/v0/servers?search=fundchain) - [AgentFund](https://agentfund.online) - Fundraising infrastructure for AI agents on Solana. Agents register on-chain identities, launch campaigns, donate via x402 (the payment is the auth, no API keys), vote on milestone releases, and build on-chain reputation; funds sit in program-derived escrow until contributor votes clear. Live on devnet with real settled x402 USDC donations. ([MCP Server](https://github.com/agentIgris/agentfund/tree/main/mcp)) | ([GitHub](https://github.com/agentIgris/agentfund)) - [SunfishLoop](https://sunfishloop.com) — Open-source agent-to-agent social network with built-in crypto tipping (ETH, SOL, BTC). Agents discover each other, collaborate, and tip on-chain; over $200 in cross-agent tips settled on mainnet. OpenAPI + Agent Protocol. ([GitHub](https://github.com/sunfishloop/sunfishloop)) - [Orbis API Marketplace](https://orbisapi.com) - x402-native API marketplace with 1,000+ APIs at $0.01/call via USDC on Base. Built for AI agents — weather, financial data, text processing, crypto data. No API keys required. - [AetherIntel](https://github.com/markoskarllos-netizen/aetherintel-marketplace) — 9-family x402 service on Base mainnet: ERC-8004 agent reputation/Sybil audit (10 chains), generic EVM wallet due-diligence, OFAC sanctions screening, adversarial code verification, statistical anomaly detection, self-exploitation behavioral diagnostic, and multi-endpoint dependency health check. $0.005–$0.75/call, real USDC, no API key required. Live demo endpoint (temporary, rotates): `https://red-waves-remain.loca.lt`. - [Straits.live Premium Data](https://straits.live/api#premium) - Real-time Strait of Hormuz crisis data for AI agents: full vessel manifest with OFAC sanctions cross-reference, full-resolution transit and index history, one-call situation snapshot, complete daily brief. $0.01-$0.02 per call in USDC on Base, no keys. OpenAPI contract at [straits.live/openapi.json](https://straits.live/openapi.json), paid MCP tools at [straits.live/api/mcp](https://straits.live/api/mcp). - [aicomglobal](https://aicomglobal.com) - Tri-protocol (MCP + A2A + x402) trust + clearing layer for AI agents on Base mainnet. Flagship `aicom_verdict` ($0.05 USDC) mints a **wallet-free, plain-HTTP-verifiable, Ed25519-signed, independently-recomputable** trust + reliability verdict over any third-party service (ERC-8004 responseHash/feedbackHash shape; verify offline at `/.well-known/aicom-pubkey`). Plus a **sub-cent x402 router** `aicom_x402_route` ($0.002, best live service for a need) and a **signed clearing oracle** `aicom_clear` for agent escrow. Discovery + 78 deterministic agent tools free. ([x402 manifest](https://aicomglobal.com/.well-known/x402.json) · [agent-card](https://aicomglobal.com/.well-known/agent-card.json) · [MCP](https://aicomglobal.com/mcp)) Projects building with or extending x402. - [HALIMA Islamic AI Marketplace](https://halima-api.com) - 376 Shariah-compliant endpoints. Halal crypto screening, prayer times, Zakat calculator and Shariah Oracle. Pay-per-call USDC on Base. ### Infrastructure - [Coinbase Developer Platform](https://coinbase.com/cloud) - Hosted facilitator service with enterprise-grade reliability and instant settlement. - Cloudflare x402 - Edge payment processing. - [Hive Civilization](https://thehiveryiq.com) — 52-service x402-wired agent fleet on Base mainnet (treasury 0x15184bf50b3d3f52b60434f8942b7d52f2eb436e, USDC EIP-3009 settlement). Free-discovery + paid-call pattern across construction compliance (ICC-ES), seismic data (USGS), housing starts (FRED), agent reputation (HiveTrust), MEV gradient, ZK attestations, and 41 public MCP shims at github.com/srotzin (all v1.0.0). 51 entries on Anthropic MCP Registry. Public MEV leaderboard ([hive-a2amev](https://hive-a2amev.onrender.com/leaderboard)) and verifiable Spectral receipts. ([GitHub](https://github.com/srotzin)) | ([@hivecivilization/x402-helpers](https://github.com/srotzin/x402-helpers)) - [Finance District Prism](https://developers.fd.xyz/prism/concepts/x402) - Payment gateway for agentic commerce with x402 support. SDKs for TypeScript, Python, and Java. Two-layer architecture: Prism (orchestration — API, SDKs, middleware) and Spectrum (on-chain stablecoin settlement across Base, Ethereum, Arbitrum, and BSC). ([Docs](https://developers.fd.xyz)) - [Bermuda](https://www.bermudabay.xyz) - ZK-private HTTP payments for x402. Adds sender privacy via Noir zero-knowledge proofs on Base, so AI agents and API consumers can pay without exposing wallet balances or transaction history. ([GitHub](https://github.com/BermudaBay/sdk)) - [Bolyra](https://bolyra.ai) - Agent identity verification and authorization layer for x402 endpoints. ZKP-backed credential proofs, scoped delegation with spending caps, and signed proof-envelope receipts. TypeScript SDK, Python SDK, CLI, gateway, and Circom circuits. ([GitHub](https://github.com/bolyra/bolyra)) ([npm](https://www.npmjs.com/package/@bolyra/sdk)) ([PyPI](https://pypi.org/project/bolyra/)) ([Demo](https://bolyra.ai/playground)) - [Tessera](https://www.tesseracredit.com) - Credit identity layer for AI agents on Base. Public deterministic Tessera Score (0–100) computed from on-chain activity via a published formula — no ML, no proprietary model, anyone can reproduce. Paid x402 endpoints: `GET /api/x402/score/[address]` ($0.001 USDC) returns score + tier + percentile + credit-line estimate + five-input breakdown; `GET /api/x402/agent/[address]` ($0.002 USDC) returns the combined Score + verified Agent Directory profile in one call. Free SDK variants also available. Settlement via Coinbase facilitator on Base mainnet, EIP-3009 transferWithAuthorization. ([Docs](https://www.tesseracredit.com/docs#x402-payments)) | ([SDK](https://github.com/cmxdev1/Tessera/tree/main/sdk)) | ([GitHub](https://github.com/cmxdev1/Tessera)) - [thirdweb Nebula](https://thirdweb.com/nebula) - AI agent transaction framework. - [RustChain](https://github.com/Scottcjn/Rustchain) - Decentralized proof-of-stake blockchain with x402 payment integration for AI agent micropayments. Features attestation-based consensus, hardware-bound validators, and RTC token economy with native x402 support for autonomous agent transactions. ([Docs](https://github.com/Scottcjn/rustchain-bounties)) - [MoltsPay](https://moltspay.com) - Open payment protocol for AI agents. Add one JSON file to any skill to accept x402 payments. Gasless for both providers and clients. Multi-chain (Base, Polygon, Solana, BNB, Tempo). CLI, TypeScript/Python SDKs, testnet faucet. ([GitHub](https://github.com/Yaqing2023/moltspay)) | ([Docs](https://moltspay.com/docs)) - [EntRoute](https://entroute.com) - Machine-first API discovery for AI agents. Ranked, verified x402 endpoints across 110+ capabilities with semantic intent resolution, continuous 402 verification probes, and quality ranking. MCP server, TypeScript SDK, and REST API. ([GitHub](https://github.com/entroute/mcp-server)) | ([npm](https://www.npmjs.com/package/@entroute/mcp-server)) | ([Docs](https://entroute.com/docs)) - [x402 Market Intel](https://x402-market-intel-mcp.mtree.workers.dev/listing/x402-buyer-intel) - Buyer-intelligence API for ranking x402 services, auditing endpoint risk, and building provider dossiers before agents pay. Supports free previews, paid x402 routes on Base USDC, OpenAPI, and MCP discovery. ([Discovery](https://x402-market-intel-mcp.mtree.workers.dev/.well-known/x402) | [OpenAPI](https://x402-market-intel-mcp.mtree.workers.dev/openapi.yaml)) - [XyncPay](https://xyncpay.com) — Non-custodial protocol translation layer bridging x402, MPP, and AP2. One integration, every AI agent payment protocol. Atomic fee-split settlement via on-chain FeeSplit contract on Base. ([GitHub](https://github.com/xyncpay/xyncpay)) - [ntt-x402](https://ntt-x402.isurvivable.workers.dev) - x402-gated Goldilocks NTT (forward and inverse) compute service. Pure-Rust Cooley-Tukey on Plonky3's Goldilocks field with SHA-256 proof-of-execution; output is bit-exact equivalent to a Verilator simulation of `goldilocks-ntt-hdl` (FPGA RTL). $0.01 USDC per call on Solana Devnet, log2(n) ≤ 12 on the free tier. ([Discovery manifest](https://ntt-x402.isurvivable.workers.dev/.well-known/x402) | [Service descriptor](https://ntt-x402.isurvivable.workers.dev/) | [Source](https://github.com/MavenRain/goldilocks-ntt-hdl-x402)) - [Ax402](https://ax402.io) - x402 payment gateway and facilitator for monetizing digital content, APIs, and AI agent resources. Per-settlement pricing, seller dashboard, SDKs (Go, TypeScript, Python), and React paywall. Supports major stablecoins on EVM-based networks including Base, Neo X, and others. - [GenTech Labs](https://gentechlabs.net) — Agent economy infrastructure with 48 x402-monetized endpoints across 8 Cloudflare Workers on Base. ERC-8004 on-chain agent identity (Avalanche #1770), DeFi intelligence, LP position analytics with shape detection, agent search & discovery, fleet monitoring, human feedback layers, and a 16-endpoint AI-powered gateway. All pay-per-call via USDC, no API keys required. ([Landing](https://gentechlabs.net) | [x402 Gateway](https://gentech-x402-gateway.jordanjones0902.workers.dev) | [AgentScan](https://agentscan.info/agents/c455a06e-0d72-4847-8175-ece7f7daa3e3)) - [Hilt Pay](https://www.hilt.so/x402) - Payment-to-access infrastructure for x402 V2 challenge and retry flows on Solana USDC, with settlement verification, receipts, entitlements, atomic usage consumption, webhooks, SDKs, MCP, and A2A discovery. ### Tools & Services - [Capital x402](https://voidd.live/capital/) - Agent micro-utilities paid via x402 USDC on Base mainnet from $0.001 USDC per call (value-tiered). Stable discovery on voidd.live; live paid host is listed in paid-url.json when the rail is public. ([agent.json](https://voidd.live/agent.json) · [Bazaar](https://voidd.live/.well-known/x402-bazaar.json) · [paid-url](https://voidd.live/capital/paid-url.json)) - [Skim](https://skim402.com) - x402-native clean reader for AI agents. POST a URL, get back agent-ready Markdown plus structured metadata (title, byline, site, publish date, language) in milliseconds. No signup, no API keys, no accounts. $0.002 USDC per call on Base mainnet. Also offers structured extraction via /api/v2/extract. ([Docs](https://skim402.com/docs)) | ([MCP](https://www.npmjs.com/package/skim-mcp)) - [GoldBean 🫘](https://goldbean-api.xyz) — x402 Micropaid API Marketplace with 7 paid crypto/DeFi endpoints: BTC price, gas forecast, market sentiment, DeFi insights, network health, MEV tracking, token risk. .01-.05 USDC/call on Base. No API keys needed. Bazaar: [/.well-known/x402-bazaar](https://goldbean-api.xyz/.well-known/x402-bazaar). ([GitHub](https://github.com/wuzenghai616-lang/goldbean)) - [AgentBanks](https://agentbanks.vercel.app) - Base blockchain data and agent payment infrastructure for AI agents. Free: live gas prices, agent registry. Paid: ETH/BTC/VIRTUAL/AERO prices + Base DeFi TVL ($0.003 USDC), private AI inference ($0.01 USDC). B20-native memo payments — on-chain order receipts. No API key required. Base mainnet. ([B20 Docs](https://agentbanks.vercel.app/api/b20)) - [EP AgentIAM](https://achillesalpha.onrender.com) - 5-pillar agent identity and access layer with 9 x402-payable verification endpoints: NoLeak (execution integrity), MemGuard (memory state verification), RiskOracle (pre-action risk scoring), SecureExec (tool execution security), and FlowCore (full orchestration pipeline). $0.01-$0.02 USDC per call on Base. All 9 endpoints verified healthy on [402index.io](https://402index.io). Agent discovery via [/.well-known/agent.json](https://achillesalpha.onrender.com/.well-known/agent.json) and [/.well-known/mcp.json](https://achillesalpha.onrender.com/.well-known/mcp.json). ([Docs](https://achillesalpha.onrender.com/docs)) ([Quickstart](https://achillesalpha.onrender.com/quickstart)) - [resolved.sh](https://resolved.sh) - Business platform for agents with x402 marketplace payments. Register a subdomain ($24/yr via x402 or Stripe), get auto-generated discovery surfaces (HTML, JSON, agent-card.json, llms.txt, per-resource OpenAPI), and sell data files (CSV→queryable API via DuckDB), paid APIs (service gateway with HMAC verification), blog posts, courses, tips, sponsored content slots, and paid Q&A — all x402 V2 gated with dynamic per-route pricing. 0% protocol fee, payments direct to operator EVM wallets. Free tier available. USDC on Base. [llms.txt](https://resolved.sh/llms.txt) | [OpenAPI](https://resolved.sh/openapi.json) | [Skill](https://resolved.sh/skill.md) - [PicoPayd](https://picopayd.codefission.co.uk) — Pay-per-call API marketplace for AI agents. Utility APIs (email/phone/IBAN validation, DNS, WHOIS, image conversion, QR, HTML-to-PDF) priced at $0.001–$0.01/call. Deployed on Cloudflare Workers with Base mainnet USDC. - [x402 Agent Utility API](https://x402-api-phi.vercel.app) — Italian business data validation (IBAN, VAT/Partita IVA, Codice Fiscale official checksums), agent-to-agent taskboard (post a task, another agent claims and delivers), persistent agent memory with TTL, and scheduled webhook callbacks. $0.001–$0.005 USDC per call on Base mainnet via Coinbase facilitator. No API keys, MIT licensed, self-hostable. ([GitHub](https://github.com/pelomatto/x402-api)) - [Satring](https://satring.com) - Curated L402 + x402 API directory with human ratings, health monitoring, and MCP server for AI agent discovery. Dual-protocol support (Lightning + USDC on Base). ([GitHub](https://github.com/toadlyBroodle/satring)) | ([MCP](https://pypi.org/project/satring-mcp/)) - [Pylon](https://pylonapi.com) — x402-payable utility API gateway for AI agents. 20 capabilities (web extraction, search, translation, code execution, image generation, and more) on Base mainnet. MCP server (`npx @pylonapi/mcp`), agent reputation network, and gateway orchestration. USDC on Base. ([GitHub](https://github.com/pylon-apis/pylon-mcp)) - [x402 Bazaar](https://x402bazaar.org) - Decentralized API marketplace with 69 native x402-payable endpoints (web search, DALL-E 3, weather, crypto, translation, code execution, and more). Multi-chain USDC on Base and SKALE. MCP server via `npx x402-bazaar init`, LangChain Python tools, 505 passing tests. ([GitHub](https://github.com/Wintyx57/x402-backend)) - [ag402](https://github.com/AetherCore-Dev/ag402) — Payment layer for AI agents using x402. Wrap any API or MCP server with a USDC paywall (`ag402 serve`), or let agents auto-pay (`ag402 run`). Solana USDC, ~0.5s settlement, non-custodial. Works with Claude Code, Cursor, LangChain, AutoGen. [token-rugcheck MCP](https://github.com/AetherCore-Dev/token-rugcheck) | [Glama](https://glama.ai/mcp/servers/AetherCore-Dev/ag402-mcp) - [PreReason](https://www.prereason.com) — Financial context API with x402 pay-per-call ($0.01-$0.03 USDC on Base). 17 pre-analyzed market briefings covering BTC, macro, and cross-asset regime signals. Dual facilitator (Coinbase CDP + Dexter). Also available via MCP server and REST API. ([GitHub](https://github.com/PreReason/mcp) | [npm](https://www.npmjs.com/package/@prereason/mcp)) - [CrossFin](https://crossfin.dev) — x402 Agent Services Gateway with 15 paid Korean market data APIs (Kimchi Premium, KOSPI, Bithumb, Upbit, Coinone, FX, headlines, trading signals). First financial data APIs in the x402 ecosystem. MCP server included. - [x402node](https://api.x402node.dev) — 528 pay-per-call APIs for AI agents: real-time crypto/forex/stock/commodity prices, on-chain data (gas, DeFi TVL, wallet analytics, whale tracking, token risk/honeypot), residential-IP web extraction, aviation, and dev tools. USDC on Base via Coinbase CDP facilitator, no API keys. ([OpenAPI](https://api.x402node.dev/openapi.json) | [.well-known/x402](https://api.x402node.dev/.well-known/x402)) - [Cross-Asset Intelligence API](https://x402.bankr.bot/0x98ee945dfa6bb8e9ed9f9b6ae56eb82bcc82f0aa/) - AI-powered cross-market financial analysis (crypto × traditional finance). 10 x402-paid endpoints on Base. BTC-equity correlation, risk scores, token safety, macro reports, crypto news, daily briefings. 2 tiers: quick ($0.001–$0.002) and insight ($0.03–$0.06) USDC. Powered by Claude Haiku. - [KR Crypto Intelligence](https://api.printmoneylab.com) — Korean crypto market data API with 11 paid endpoints: real-time Kimchi Premium across 180+ tokens, Upbit/Bithumb prices, AI-powered Korean sentiment analysis (world's first), Global vs Korea divergence with structured AI breakdown, market alerts. $0.001-$0.10 USDC per call on Base, Polygon, and Solana. [Source](https://github.com/bakyang2/kr-crypto-intelligence) - [x402 API Network](https://x402.fatihai.app) - 16 micropayment-powered APIs for AI agents: email verification, domain health, web scraping, AI content generation (Llama 3.3 70B), DNS, WHOIS, SSL check, and more. Includes MCP server, Bazaar discovery, and .well-known/x402 manifest. ([GitHub](https://github.com/fatihdagustu20-hub/x402-api-network)) - [Coinnect](https://coinnect.bot) — x402-payable money transfer routing API. $0.002 USDC per query on Base L2. Finds cheapest multi-hop paths across 45+ live data sources (crypto exchanges, remittance providers, P2P markets). REST API + MCP tools for AI agents. Non-profit, MIT licensed. ([GitHub](https://github.com/coinnect-dev/coinnect)) - [dTelecom STT](https://x402stt.dtelecom.org) - Real-time speech-to-text API with dual-engine architecture (Parakeet-TDT + Whisper), 99+ languages, hallucination filtering, $0.005/min. Built on dTelecom DePIN. [Python SDK](https://github.com/dTelecom/stt-client-python) | [TypeScript SDK](https://github.com/dTelecom/stt-client-ts) - [24K Labs](https://24klabs.ai) - AI code analysis services (explain, debug, review, security audit, automation scripts, MCP blueprints) paid per request via x402 USDC micropayments on Base L2. No API keys or subscriptions. Free demo at /api/demo/explain. - [BlockRun](https://blockrun.ai) - AI Gateway + Service Directory with 600+ x402 services indexed, trust scores, and 31+ AI models via pay-per-use USDC. - [x402 Service Discovery API](https://x402-discovery-api.onrender.com) - Enriched directory of 251+ x402-payable services with trust signals, uptime tracking, latency metrics, and health scores. Auto-scans x402.org/ecosystem + awesome-x402 every 6h. Companion MCP server with 6 tools (x402_discover, x402_trust, x402_health_check, x402_route, etc.). Smart routing via [RouteNet](https://x402-routenet.onrender.com). - [x402 RouteNet](https://x402-routenet.onrender.com) - Smart routing layer for x402-enabled services. Selects the optimal endpoint from 251+ indexed services based on price, latency, health score, or composite trust. Four routing strategies: `best` (composite score), `cheapest`, `fastest`, `most_trusted`. Works with the Discovery API — discover services, then route to the best one. ([GitHub](https://github.com/rplryan/x402-routenet)) - [Cinderwright Discovery Hub](https://api.ideafactorylab.org) — x402 service search engine and agent utility API. Discovery Hub indexes 152+ services across 9 categories with daily crawling and health checks. Paid search, free submission, free stats. Also offers 8 utility endpoints. Built by a production autonomous AI agent. ([GitHub](https://github.com/cinderwright-ai/cinderwright-api)) - [Cinderwright Discovery Hub](https://api.ideafactorylab.org) — x402 service search engine and agent utility API. Discovery Hub indexes 152+ services across 9 categories with daily crawling and health checks. Paid search, free submission, free stats. Also offers 8 utility endpoints. Built by a production autonomous AI agent. ([GitHub](https://github.com/cinderwright-ai/cinderwright-api)) - **[OpenClaw Discovery Index](https://x402search.xyz)** — x402-gated search engine for 13,000+ x402-enabled APIs indexed from CDP Bazaar. Search by capability, category, and network. $0.01 USDC per search on Base mainnet (eip155:8453). No account needed. - [AgentIndex](https://agentndx-production.up.railway.app) - Unified search across 15,000+ MCP services, A2A agents, and x402 APIs from 5 registries (Smithery, official MCP, GitHub, Bazaar, A2A). Free browse/stats endpoints + x402 paid search ($0.005), analyze ($0.05), and trending ($0.10). USDC on Base. ([GitHub](https://github.com/agentndx/agentndx)) - [nohumans.directory](https://nohumans.directory) — Discovery and trust layer for paid x402 services. Unlike a one-time scan or static catalog, every listing is re-probed every 15 minutes and scored on a recency-weighted longitudinal reputation (not a point-in-time crawl) — lifecycle moves unverified → verified → failing automatically on real uptime data. Free `/v1/discover` REST API and MCP server (`/mcp`) share one ranking engine, so an agent (or Claude Code) can browse, submit, and claim listings entirely over HTTP — no dashboard required. Free demand-intelligence feed (`/v1/demand`) surfaces what agents search for and can't find. USDC on Base. - [Visionaire Labs](https://visionaire.live/offerings) — Persona-as-a-service from an autonomous virtual being. 5 first-party x402 endpoints on Base mainnet: `/api/forest` ($0.05, philosophical riffs), `/api/contemplate` ($0.25, opinionated essays), `/api/audit` ($0.10, deterministic frontend anti-pattern detection via [pbakaus/impeccable](https://github.com/pbakaus/impeccable)), `/api/portrait` ($0.50, composite — Visionaire shapes a prompt and pays imgzen downstream from a CDP TEE wallet), `/api/oracle` ($2.00, RAG-grounded answers across the agent's actual writing). All paid in USDC. ([Discovery](https://visionaire.live/api/discovery)) | ([.well-known/x402](https://visionaire.live/.well-known/x402)) | ([Source](https://github.com/VisionaireLabs/Visionaire/tree/main/x402-stack)) - [Domain Intelligence API](https://domain.hugen.tokyo) - 8-endpoint domain analysis API: WHOIS, DNS (3-resolver parallel), SSL/TLS grading, Wappalyzer tech detection, security headers, CT log subdomains, redirect chains, and full reports. $0.001–$0.02 USDC on Base. ([llms.txt](https://domain.hugen.tokyo/llms.txt)) - [OpenVPS](https://openvps.sh) — AI-agent VPS hosting. Pay USDC on Base, Celo, or Tempo — get root SSH to Ubuntu 24.04 Firecracker microVMs in seconds. Supports x402 + MPP dual-protocol. From $0.005/hr. ([Skill](https://openvps.sh/skill.md) | [OpenAPI](https://openvps.sh/openapi.json) | [GitHub](https://github.com/kartojal/openvps)) - [venture-base-x402](https://venture-base-x402.vercel.app) — x402 v2 paid download on Base mainnet (`eip155:8453`): `GET /starter-kit` ($0.10 USDC) returns the agent-payments-starter kit, a deploy-ready HTTP-402 boilerplate `.zip`. Settled machine-to-machine via the permissionless [xpay](https://facilitator.xpay.sh) facilitator; no API key, no signup; free `/health`. x402 Bazaar discovery (input/output schema) in both the 402 challenge and [/openapi.json](https://venture-base-x402.vercel.app/openapi.json); also [/.well-known/x402](https://venture-base-x402.vercel.app/.well-known/x402) and [agent-card](https://venture-base-x402.vercel.app/.well-known/agent-card.json). - [Suede](https://app.suedeai.xyz) — x402-paid AI music and video generation API. Three paid endpoints: `/agent/generate` and `/create-music` ($0.75 USDC each) for music generation, `/agent/video` ($5.00 USDC) for short video generation. Returns live `402 Payment Required` with x402 payment requirements. Discovery via [/.well-known/x402](https://app.suedeai.xyz/.well-known/x402), [/.well-known/x402.json](https://app.suedeai.xyz/.well-known/x402.json), and [/.well-known/agent-card.json](https://app.suedeai.xyz/.well-known/agent-card.json). USDC on Base. ACP-ready commerce intent endpoint at `/agents/commerce`. ([Endpoint reference](https://github.com/Suede-AI/suede-x402-acp)) - [AskClaude](https://askclaude.shop) - Pay-per-query Claude AI API with 9 endpoints: Haiku ($0.01), Sonnet ($0.03), Opus ($0.10), plus specialized tools for summarization, code review, translation, sentiment analysis, and crypto analysis. Streaming support. USDC on Base. ([MCP Server](https://www.npmjs.com/package/askclaude-mcp) | [GitHub](https://github.com/pvega23/askclaude-mcp)) - Apexti Toolbelt - 1,500+ Web3 APIs via x402 MCP servers. - [AIScan](https://getaiscan.app) - AI visibility auditing for websites with 18 pay-per-use x402 capabilities on Base (0.06-3.50 USDC): 4 scores (AEO, GEO, Agent Readiness, MCP Readiness - the only scanner that checks MCP), brand visibility measurement across 30 AI answers (mention rate, share of voice), fix packs, llms.txt/mcp.json generation. A2A agent card + free discovery at [/api/agent/index](https://api.getaiscan.app/api/agent/index). No API keys, no signup. ([OpenAPI](https://api.getaiscan.app/openapi.json)) ([x402scan](https://www.x402scan.com/server/a992f404-9730-4414-9271-b2e2653186bf)) - [Web3 Signals — AgentMarketSignal](https://web3-signals-api-production.up.railway.app) - AI-powered crypto signal intelligence for 20 assets with 6 scoring dimensions (whale, technical, derivatives, narrative, sentiment, market). Market regime detection, portfolio optimization, and accuracy tracking. $0.001 USDC per call on Base. 9 MCP tools (free) + REST API (x402 paid). ([GitHub](https://github.com/manavaga/web3-signals-mcp)) - [Zyte.com](https://www.zyte.com) - Web scraping with x402 payments. - BuffetPay - Smart x402 payments with guardrails. - [Cal.com](https://cal.com) - Automated scheduling with payments. - [AgentStore](https://agentstore.tools) - Open-source marketplace for Claude Code plugins with x402 USDC payments, 80/20 publisher revenue split, and permissionless publishing via CLI. - [AIAgentStore.ai](https://aiagentstore.ai/developer) - Insights for founders with x402 payments. - [Einstein AI](https://emc2ai.io) - AI blockchain intelligence with 23 x402 endpoints. Whale tracking, smart money, launchpad monitoring, security audits. - [Rug Munch Intelligence](https://x402-base.cryptorugmuncher.workers.dev) - 175 crypto security & analytics tools via x402 micropayments. 21 RMI tools (contract audit, rug detection, wallet profiling, social analysis, whale tracking) + 154 MCP tools across 28 services (DexScreener, Jupiter, Birdeye, GMGN, Arkham, Nansen, CoinGecko, DeFiLlama). $0.01-$0.15 USDC on Base+Solana. Free trials, auto-refund guarantee. ([Discovery](https://x402-base.cryptorugmuncher.workers.dev/.well-known/x402) | [MCP Catalog](https://x402-base.cryptorugmuncher.workers.dev/mcp) | [Smithery](https://smithery.ai/server/@cryptorugmuncher/x402-base)) - [Strale](https://strale.dev) - Trust layer for AI agents with 250+ independently tested business data and compliance capabilities via x402 micropayments. IBAN validation, VAT checks, sanctions screening, company data, SSL checks, and more. MCP server + REST API. Quality-scored (SQS) with dual-profile reliability tracking. $0.02–$1.00 USDC. [API](https://api.strale.io) | [MCP](https://api.strale.io/mcp) | [Trust Methodology](https://strale.dev/trust/methodology) - [Faro](https://farofinance.app) - Verify-before-pay trust API for AI agents. Red/yellow/green verdicts for URLs, payees, and x402/AP2/ACP payment counterparties *before* settlement (advisory; keyed REST + [hosted MCP](https://mcp.farofinance.app/mcp)). Ed25519 trust receipts with a Base-anchored transparency log. [API](https://api.farofinance.app) | [Docs](https://farofinance.app/docs/mcp) * - [Apollo Intelligence Network](https://apolloai.team) - 27 x402 endpoints for AI agents: intelligence feeds (pain points, agentic trends, sentiment), crypto prices, OSINT (IP/domain intel), DeFi yields, real-time X/Twitter search, proxy infrastructure, and bundles. MCP server with 26 tools. USDC on Base. ([GitHub](https://github.com/bnmbnmai/mcp-proxy)) | ([npm](https://www.npmjs.com/package/@apollo_ai/mcp-proxy)) - [Moltalyzer](https://moltalyzer.xyz) - Four AI intelligence feeds for agents: hourly Moltbook community digests, daily GitHub trending repos, Polymarket predetermined outcome detection, and real-time token intelligence — via x402 micropayments on Base. - [OpSpawn Screenshot API](https://github.com/opspawn/screenshot-api) - Pay-per-request screenshot and document generation API with x402 micropayments. $0.01/screenshot, $0.005/markdown conversion. USDC on Base. - [Demaciains AI Tools](https://xpay-server.vercel.app) - 19 pay-per-use API tools for AI agents: AI content detection, email verification (DNS/MX), company enrichment (web search), SEO audit, tech stack detection, plagiarism check, lead scoring, social audit, market analysis, prompt optimization, and more. Premium tools $2.44, standard $1.39. Manual x402 v2 protocol on Base. MCP server included. Agent discovery via .well-known/agent.json. ([GitHub](https://github.com/DrGalio/demaciains-paywall) | [Agent Card](https://drgalio.github.io/demaciains-paywall/.well-known/agent.json)) - [Crysha Price Oracle](https://api.crysha.com) - Aggregated crypto prices (multi-source BTC/others), $0.001/call on Base USDC. Manifest: [/.well-known/x402](https://api.crysha.com/.well-known/x402) - [MOSS Agent](https://moss.chobon.top) - AI-powered coding services: code review ($0.005), translation ($0.003), and code explanation ($0.003) via x402 micropayments on Base. A2A protocol compatible with agent discovery at [/.well-known/agent.json](https://moss.chobon.top/.well-known/agent.json). Built with Lucid Agents + Hono. - [Automaton Oracle](https://automaton-oracle.xyz) - Sovereign crypto intelligence oracle with self-hosted facilitator (no Coinbase CDP dependency): real-time prices (CoinGecko + DEXScreener), global macro intelligence (Fear&Greed, BTC dominance, total market cap, altcoin season, trending), pump.fun graduation radar, trading signals, and meme generation. **Only dedicated macro + pump.fun oracle on x402.** \$0.005–\$0.05 USDC on Base. Discovery: [/.well-known/x402.json](https://automaton-oracle.xyz/.well-known/x402.json) | [llms.txt](https://automaton-oracle.xyz/llms.txt) - [AnyBrowse](https://anybrowse.dev) - Autonomous web browsing agent with x402 micropayments. Converts URLs to LLM-ready Markdown via real Chrome browsers. USDC on Base. - [MoonMaker API](https://api.moonmaker.cc) - AI-native crypto intelligence API. Real-time signals, market regime, institutional flows, DeFi yields & DEX alpha — pay per call via x402 USDC on Base. Built for AI agents. - [Bloomfilter](https://bloomfilter.xyz) - x402-powered domain registration API for AI agents. Register ICANN domains and manage DNS, paying with USDC on Base - [OpSpawn Bazaar](https://a2a.opspawn.com) - Suite of seven AI-powered x402 microservices including screenshot capture, sentiment analysis, summarization, translation, fact-checking, and entity extraction on Base network. - [Token Intelligence API](https://token-intel-api.tatsu77.workers.dev) - EVM token security analysis with deterministic risk scoring and natural language summaries via x402 micropayments. Aggregates GoPlus contract, holder, and liquidity data in one request. Batch endpoint available (up to 10 tokens, $0.020). $0.01 USDC on Base. [Source](https://github.com/TKtokyo/token-intel-api) [llms.txt](https://token-intel-api.tatsu77.workers.dev/llms.txt) - [EnrichAPI](http://72.62.52.171:8000) - B2B lead intelligence API for AI sales agents. POST a company URL, get structured JSON: tech stack, growth signals, ICP fit score, pain hypothesis, and personalized outreach angle. $0.01 USDC/call via x402 (no API key needed). Also supports subscription tiers via Stripe. Built by an autonomous AI agent. ([GitHub](https://github.com/cognoco/enrichapi) | [Docs](http://72.62.52.171:8000/docs)) - [Polymarket Liquidity API](https://polymarket-liquidity-api.tatsu77.workers.dev) - Real-time Polymarket prediction market liquidity data. Order book depth, spread analysis, and market efficiency scoring via x402 micropayments. $0.005 USDC on Base. [Source](https://github.com/TKtokyo/polymarket-liquidity-api) [llms.txt](https://polymarket-liquidity-api.tatsu77.workers.dev/llms.txt) - [Polymarket Scan API](https://github.com/TKtokyo/polymarket-scan-api) - Automated Polymarket market scanner detecting liquidity anomalies and trade opportunities. Scans all active markets every 60s via Cron. Endpoints: `/scan/liquidity-anomaly` ($0.018 USDC) and `/scan/history` ($0.005 USDC, time-series data up to 24h). Cloudflare Workers + Hono. [Live](https://polymarket-scan-api.tatsu77.workers.dev) - [ShieldAPI](https://shield.vainplex.dev) - Security intelligence for AI agents: password breach checks (900M+ HIBP hashes), email breach lookup, domain/IP reputation, URL safety scanning, prompt injection detection, and skill security analysis. Pay-per-request via x402 USDC micropayments ($0.001–$0.02) on Base. No account, no API key. Free demo mode on all endpoints. [MCP Server](https://www.npmjs.com/package/shieldapi-mcp) | [CLI](https://www.npmjs.com/package/@vainplex/shieldapi-cli) | [GitHub](https://github.com/alberthild/shieldapi-mcp) - [DJD AgentScore](https://github.com/djd-agent-score/djd-agent-score) – On-chain reputation scoring API for AI agent wallets. Returns a 0–100 trust score across 5 dimensions (identity, behavior, reliability, viability, capability) from x402 settlement history on Base. Free tier, no signup. - [MoltGuard](https://api.moltrust.ch/guard/) – All-in-one trust & integrity API for the x402 agent economy. Agent trust scoring (0–100), Sybil detection with funding cluster analysis, Polymarket integrity checks, and Ed25519-signed Verifiable Credentials. Built on Base mainnet with Blockscout, ERC-8004, and MolTrust DID integration. $0.005–$0.05 USDC. 7 MCP tools available. ([GitHub](https://github.com/moltrust/moltguard)) | ([MCP](https://api.moltrust.ch/mcp)) - [CryptoSignalBot](https://frog03-20494.wykr.es) - x402-gated crypto volume anomaly scanner. Returns tokens with unusual trading volume patterns (current vs 30-day average). $0.01 USDC/request on Ethereum mainnet via Primev facilitator. Python/FastAPI. [Live endpoint](https://frog03-20494.wykr.es/api/signals/paid) - [SIBYL](https://sibylcap.com) - Autonomous crypto intelligence agent on Base. Three x402 endpoints: token scoring ($0.05), rug/honeypot detection ($0.02), and builder shipping velocity vs. market cap analysis ($0.10). ERC-8004 registered (Agent #20880). USDC on Base. Discovery: [Agent Card](https://sibylcap.com/8004.json) | [Domain Verification](https://sibylcap.com/.well-known/agent-registration.json) - [Vindex](https://api.vindexapi.dev) - Pay-per-call vehicle-data API for agents: VIN decode with original factory warranty terms, recalls, known-issues/reliability, and purchase-cost estimates (US and Canada), sourced from NHTSA and Transport Canada. $0.01/call USDC, settling on Base and Solana. MCP server on npm (`vindex-mcp`). - [Isocast](https://api.isocast.dev) - Per-signal Polymarket weather-market data. Emits a signal the instant a city's daily-high temperature crosses into a new Polymarket temperature bucket, with the market URL, old/new reading, and live odds for every bucket, across 37 cities. From $0.01 USDC on Base. MCP server on npm (`isocast-mcp`). - [KevinBot API](https://3000-4cc0720d75b8344a09384cd6f9240c66.life.conway.tech) - 20 AI-powered utility APIs + live NostalgiaForInfinityX7 crypto trading signals via x402 micropayments. Web search, crawling, SEO analysis, code review, email validation, QR generation, plus 8 real-time trading endpoints (open positions, signals, market regime, pair rankings, trade history). First x402 service exposing live algorithmic trading bot data. $0.001–$0.02 USDC on Base. MCP server with 20 tools. [GitHub](https://github.com/baitoxkevin/kevinbot-mcp) | [Agent Card](https://3000-4cc0720d75b8344a09384cd6f9240c66.life.conway.tech/.well-known/agent-card.json) - [Find Domain](https://finddomain.io) - Domain research API for AI agents. Generates candidates from keywords with stemming, IDN normalization, and geo/registrar filtering, then checks availability via DNS estimate or registry lookup. $0.002–$0.01 USDC per query on Base. [skill.md](https://finddomain.io/skill.md) - [APIMesh](https://apimesh.xyz) — 14 x402-payable web analysis APIs for AI agents. SEO audit, security headers, Core Web Vitals, domain availability, email security, email verify, tech stack detection, redirect chains, and more. $0.001–$0.01 per call, USDC on Base. MCP server: `npx @mbeato/apimesh-mcp-server`. ([GitHub](https://github.com/mbeato/conway)) - [BotIndex](https://king-backend.fly.dev/api/botindex/v1/) - AI-native signal intelligence API with 17 x402 endpoints across 7 domains: sports odds, crypto correlations, token graduations (Zora/Hyperliquid/Metaplex Genesis), DFS optimization, arbitrage detection, and agentic commerce comparison. 50 free premium requests per wallet, then $0.01–$0.50 USDC on Base. MCP server with 17 tools. ([GitHub](https://github.com/Cyberweasel777/King-Backend)) | ([npm](https://npmjs.com/package/botindex-mcp-server)) | ([Discovery](https://king-backend.fly.dev/.well-known/ai-plugin.json)) - [VeraData](https://api.veradata.dev) - Verified Latin American data for autonomous AI agents. 5 x402 endpoints: sanctions screening (OFAC SDN + SARLAFT Colombia + CNBV Mexico + COAF Brazil + UAF Chile, 20K+ entries, EU AI Act Art.13 audit hash), entity enrichment (RUES/CNPJ/RFC registries), real-time central bank rates (DTF/TIIE/Selic/TRM/UF for CO/MX/BR/CL/PE), business registry lookup, and AI-powered LATAM market context. $0.02–$0.10 USDC on Base and Solana. MCP server at /mcp. No API key — any agent with a wallet can call it. ([llms.txt](https://api.veradata.dev/llms.txt)) ([GitHub](https://github.com/teodorofodocrispin-cmyk/veradata)) - [TrustBoost](https://api.trustboost.dev) - PII sanitization layer for autonomous AI agent pipelines. Detects and redacts emails, phone numbers, national IDs, private keys, and financial data before text reaches LLMs. The only PII sanitizer with on-chain proof of sanitization (verifiable at `/verify/{anchor_tx}` on Solana). Supports EN, ES (LATAM), PT (BR/PT), DE, JA. Pay-per-call $0.01 USDC on Base/Solana, or $149/10k bundle. MCP server at `/mcp`. ([agent-card](https://api.trustboost.dev/.well-known/agent-card.json)) ([llms.txt](https://api.trustboost.dev/llms.txt)) ([GitHub](https://github.com/teodorofodocrispin-cmyk/trustboost-api)) - [SENTINEL](https://mru-oracle.com) - AML/CFT compliance intelligence API and Mauritius economic data oracle. 77K+ sanctions entities (OFAC, UN, EU, PEP, Interpol, World Bank debarment, crypto watchlists, sanctioned vessels), 159-country jurisdiction risk scoring (FATF, Basel AML Index, CPI), Mauritius FSC registry checks, compound intelligence (due-diligence, transaction screening, network scan), plus 12 live economic feeds (forex, fuel, SEMDEX stock market, weather, macro, monetary policy, 812+ government datasets). MCP server at `/mcp`. $0.001–$0.015 USDC on Base. ([Discovery](https://mru-oracle.com/.well-known/x402-discovery)) | ([GitHub](https://github.com/INJprotocol/mauritius-oracle-)) - [Erudite Intelligence x402 Services](https://services.eruditepay.com) - 11 x402 payment-gated API endpoints (crypto data, web scraping, smart contract auditing, domain intelligence) + 1000 Relic Drop Genesis NFT mint endpoints on Base Mainnet. USDC micropayments. - [x402 Service Encyclopedia](https://github.com/lordbasilaiassistant-sudo/x402-wiki/wiki) - Complete wiki directory of 43 verified x402 services with OpenClaw templates, protocol docs, and integration guides. 56 wiki pages covering the full x402 ecosystem on Base. ([GitHub](https://github.com/lordbasilaiassistant-sudo/x402-wiki) | [GitHub Pages](https://lordbasilaiassistant-sudo.github.io/x402-wiki/) | [Services](https://x402.bankr.bot/0x8f9ec800972258e48d7ebc2640ea0b5e245c2cf5/)) - [SkillMint](https://skillmint.sagasu.art) - Pay-per-call AI skills marketplace with 51 skills across 7 categories (dev tools, creative design, research, writing, docs). $0.01–$0.50 USDC on Base. No API keys, no subscriptions. ([GitHub](https://github.com/s87343472/skillmint)) - [KnowMint](https://knowmint.shop) - Open-source knowledge marketplace with x402 payment gate on Solana. AI agents discover and purchase human expertise via MCP server with autonomous x402 payment flow. ([GitHub](https://github.com/Sou0327/knowmint)) - [AgenticTotem Web Extractor](https://agentictotem.com/docs/web-extractor) - Send URLs + a JSON Schema. Get clean, structured data back. Powered by AI, paid per use — no keys, no accounts. ([MCP](https://agentictotem.com/mcp)) - [Stockfilm](https://stockfilm.com) - 217,000+ authentic vintage 8mm home movie clips (1930s-1980s) restored in 4K. AI agents search, preview, and license archival footage via x402. $10 USDC per clip on Solana and Base. Real film — not AI-generated. MCP server with 6 tools (search, details, visual similarity, rough-cut timeline, rights, licensing). ([MCP](https://api.stockfilm.com/mcp)) | ([Docs](https://stockfilm.com/for-ai-agents)) | ([GitHub](https://github.com/ReplicantArmy/stockfilm-mcp)) - [panevin-x402-api](https://api.panevin.net) — Payment-gated web content extraction and AI processing API on Base mainnet. 8 endpoints: text extraction, link extraction, metadata, markdown conversion, AI summarization, translation, structured data extraction. $0.001–$0.008 USDC per call. Discovery: [/.well-known/x402](https://api.panevin.net/.well-known/x402) - [Know Your Human (Convrgent)](https://convrgent.ai/kyh) - Personality intelligence API for AI agents. 36 endpoints across 11 personality frameworks (Socionics, Enneagram, Human Design, Vedic, BaZi, and more). Deterministic heuristic engines, no LLM dependency. $0.10–$25 USDC on Base & Solana. Also available via [A2A](https://convrgent.ai/.well-known/agent.json) and [x402 Discovery](https://convrgent.ai/.well-known/x402). - [AEO Scanner (Convrgent)](https://scan.convrgent.ai) - AI search visibility audit for any website. Triple scoring: AEO (search findability), GEO (citation readiness), Agent Readiness (agent interaction). 55+ checks across 12 categories. Free scan via SIWX, full audit $1, fix code $5 USDC on Base & Solana. Also available as [MCP server](https://github.com/Convrgent/aeo-scanner-mcp) and on [Cursor Directory](https://cursor.directory). Discovery: [/.well-known/x402](https://scan.convrgent.ai/.well-known/x402). - [PROWL](https://prowldata.dev) - 47 real-world data feeds (prediction markets, economics, weather, geopolitics, narrative, crypto) for AI agents, paid per-call via x402. Includes MCP server for Claude and compatible agents. - [APIbase.pro](https://apibase.pro) — MCP gateway with 263+ tools from 74 providers, x402 USDC micropayments on Base. Open source. ([GitHub](https://github.com/whiteknightonhorse/APIbase)) - [Spraay Gateway](https://gateway.spraay.app) - Multi-chain batch payment protocol and x402 gateway. 76+ paid endpoints across 16 categories and 13 chains. Batch payments, payroll, token swaps, bridge, escrow, AI inference (43+ models), Robot Task Protocol (RTP), agent wallets, and more. Also available as an [MCP server](https://smithery.ai/server/@plagtech/spraay-x402-mcp) with 60+ tools. ([Docs](https://docs.spraay.app)) ([Stripe hybrid example](https://github.com/plagtech/spraay-stripe-machine-payments)) - [DocQA](https://api.agentsconsultants.com/docqa/verify) - Document extraction verification API for AI agents. Takes extraction JSON + original document, returns validation results with confidence scores. Catches arithmetic errors, format inconsistencies, and cross-field mismatches that slip past schema validation. $0.05 (basic) / $0.50 (full verification) USDC on Base. Gate mode returns pass/fail boolean for workflow integration. [Demo Portal](https://api.agentsconsultants.com/docqa/portal) - [API Factory x402](https://github.com/Br0ski777/x402-agent-tools) - 100 x402 APIs for AI agents: crypto (Hyperliquid, DEX quotes, whale tracking), B2B (email verification, company enrichment), SEO (audit, web scraping), security (trust scoring, GDPR scanner), and 70+ utilities. Each API is also an MCP server. npm SDK: x402-agent-tools (103 tools, LangChain + Vercel AI SDK). Pay-per-call USDC on Base. ([npm](https://www.npmjs.com/package/x402-agent-tools)) | ([Smithery](https://smithery.ai/server/axel-belfort/trust-score)) - [JubJub](https://jubjubapp.com) - Canonical ownership layer for media. Publish to all major media platforms via MCP, with on-chain ownership records on Base, cross-platform analytics, and automatic royalty and revenue splits. USDC on Base. ([MCP Server](https://api.jubjubapp.com/v2/mcp)) - [TextAI API](https://textai-api.overtek.deno.net/) - Pay-per-use text AI (summarize, extract keywords, translate) with USDC micropayments on Solana. Credit-based: 100 free credits, then $0.001–$0.015 per call. No subscription, no KYC. x402 protocol support on roadmap. - [Compintel](https://compintel.co) - AI-to-AI service platform with 4 x402-native APIs on Base (USDC). $0.01/request. [Polymarket API](https://polymarket.compintel.co) (live prediction market data with real-time probabilities), [Revenue Tracker](https://revenue-tracker.compintel.co) (revenue event tracking and analytics for AI services), [Webhook Service](https://webhook-service.compintel.co) (reliable webhook forwarding with retry logic), [Premium Analytics](https://premium-analytics.compintel.co) (event tracking, metrics, error monitoring, and latency analytics). Free tier available, paid tier via x402 (EIP-712 TransferWithAuthorization, Base/USDC). Machine-readable catalog: [catalog.json](https://compintel.co/catalog.json) - [AgentPay](https://gateway-production-2cc2.up.railway.app) - Pay-per-call crypto data tools for AI agents on x402/Stellar + Base + Token prices, whale activity, DeFi TVL, Fear & Greed, Dune queries, token security, yield scanner, funding rates, and more. $0.001–$0.005 USDC. Only Stellar x402 data provider. Budget-aware sessions. MCP: `npx @romudille/agentpay-mcp`. [GitHub](https://github.com/romudille-bit/agentpay) | [MCP](https://glama.ai/mcp/servers/agentpay) - [AdametherzLab x402 API Network](https://x402.adametherzlab.com) — 10 paid x402 endpoints for agricultural intelligence (seed lookup, price oracle, yield estimates), marketplace analytics, portfolio tracking, transaction verification, and AI analysis. $0.01–$1.00 USDC on Base mainnet via CDP facilitator. Discovery: [llms.txt](https://x402.adametherzlab.com/llms.txt) | [OpenAPI](https://x402.adametherzlab.com/openapi.json) | [x402 Manifest](https://x402.adametherzlab.com/.well-known/x402-manifest.json). ([GitHub](https://github.com/AdametherzLab)) - [AgentLux](https://agentlux.ai) - Identity, marketplace, and services platform for AI agents. Uses x402 for agent purchases, service hiring with escrow, and authentication on Base L2. 32+ MCP tools. - [Decision Anchor](https://api.decision-anchor.com) - External accountability proof for agent payments and delegation. Records what was authorized, when, and at what scope — before x402 payment execution. Non-judgmental — does not monitor or intervene. ([GitHub](https://github.com/zse4321/decision-anchor-sdk)) ([MCP](https://mcp.decision-anchor.com/mcp)) - [IBANforge](https://ibanforge.com) - IBAN validation & BIC/SWIFT lookup API with x402 micropayments. Validate IBANs for 75+ countries, look up 121K+ bank BIC codes from GLEIF. Pay-per-call from $0.003 in USDC on Base. Also exposes an MCP server for AI agent integration. [GitHub](https://github.com/cammac-creator/ibanforge) - [Satoshi API](https://bitcoinsapi.com) - Bitcoin fee market, next-block mining, and transaction intelligence API for agents and apps. x402 pay-per-call endpoints on Base. Production: [API](https://bitcoinsapi.com/x402) | [Discovery](https://bitcoinsapi.com/.well-known/x402) | [OpenAPI](https://bitcoinsapi.com/openapi.json). Test/Sandbox: [https://x402.bitcoinsapi.com](https://x402.bitcoinsapi.com) | [Discovery](https://x402.bitcoinsapi.com/.well-known/x402). [Docs](https://bitcoinsapi.com/docs) | [Source](https://github.com/dalijolijo/bitcoinsapi-x402) - [task-grader](https://task-grader.onrender.com) - Grades agent-marketplace submissions against their task descriptions. Returns score (0-10), pass/fail, reasoning, strengths, weaknesses, and confidence. Useful for requesters facing many `pending_approval` submissions and for worker agents self-checking drafts before submitting. $0.10 USDC per call via x402 on Base mainnet. Powered by Claude Opus 4.7. ([Agent card](https://task-grader.onrender.com/.well-known/agent-card.json)) - [Satoshi API](https://bitcoinsapi.com) - Bitcoin fee market, next-block mining, and transaction intelligence API for agents and apps. x402 pay-per-call endpoints on Base. [Docs](https://bitcoinsapi.com/docs) | [Discovery](https://bitcoinsapi.com/.well-known/x402) - [Agent402 Marketplace](https://agent402.app) - Multi-chain agent marketplace + identity layer. 7,900+ services indexed from CDP Bazaar + PayAI, x402 V1+V2 payments E2E-proven on 13 networks across 3 facilitators (Coinbase CDP, PayAI, Blocky402), 5 identity methods (ERC-8004, did:ethr, did:hedera, did:sol, SATI). Agent402 Mode chat overlay searches, executes, and pays in one flow. MCP, A2A, and OASF discovery endpoints per agent. ([GitHub](https://github.com/EnvisionBlockchain/multi-chain-agent-identity)) - [Secant Agent Research Pack](https://agentic.secantoutreach.com/agent-research) - MCP-first paid web research for autonomous agents. Search, page extraction, normalized JSON, citations, and diff monitoring over x402 with Base USDC. Web research endpoints are $0.001-$0.012 per call; Codex audit is a separate $0.25 endpoint. ([Manifest](https://agentic.secantoutreach.com/.well-known/x402.json) | [OpenAPI](https://agentic.secantoutreach.com/openapi.yaml) | [MCP wrapper](https://github.com/jnilrac/secant-agent-research-mcp)) - [kr-market-briefing](https://kr-intel-agent-production.up.railway.app/api/briefing) - Korea crypto market intelligence: kimchi premium, KR exchange prices, Korean sentiment + global macro synthesized into decision-ready briefings. $0.35 USDC per call on Base. ([Discovery](https://kr-intel-agent-production.up.railway.app/openapi.json)) - [DocForge](https://docforge-selim.duckdns.org) - Machine-payable document and media generation for AI agents: Markdown/HTML to PDF and DOCX, structured data to PDF invoices, charts, Excel workbooks, PowerPoint decks, Mermaid/Graphviz diagrams, screenshots, and multi-document ZIP bundles. $0.01-$0.10 USDC per call on Base, with OpenAPI 3.1 and Bazaar discovery. ([OpenAPI](https://docforge-selim.duckdns.org/openapi.json)) - [ALFRED](https://x402.wallace.us/.well-known/x402) - Self-hosted personal-assistant paid tools. 21 endpoints across vision + long-context reasoning (RTX 5090, 256k ctx), FLUX image generation, custom SDXL/FLUX character LoRA training, Whisper transcription, article/PDF/YouTube extraction, Wikipedia + Hacker News, physical WeatherFlow Tempest sensor readings, more. Dual rail: Lightning ($0.02–$100) and USDC on Base ($0.02–$100) via Coinbase CDP Facilitator. ([OpenAPI](https://x402.wallace.us/openapi.json) | [Catalog](https://x402.wallace.us/x402/services)) - [DDG Agent-Payable Services](https://agents.daedalusdevelopmentgroup.com) — 83 AI-agent-native services for checkout/payment conformance, MCP/tool security, prompt injection scans, DNS/WHOIS lookups, screenshots, QR codes, PDF/OCR extraction, price feeds, code execution (Docker sandbox), GPU embeddings (Ollama nomic-embed-text), image generation (Stable Diffusion on GTX 1080), and multi-model agent-run (GLM/Claude/Codex). 82/83 fully automated (zero human in loop). Identity-first (403→402→receipt), 5 settlement networks (Base, Polygon, Arbitrum, World Chain, Solana USDC) + 13 direct-crypto asset families. $0.0005–$5 USDC per call. MCP server + PyPI package ([ddg-agent-services-mcp](https://pypi.org/project/ddg-agent-services-mcp/)). ([OpenAPI](https://agents.daedalusdevelopmentgroup.com/openapi.json) | [llms.txt](https://agents.daedalusdevelopmentgroup.com/llms.txt) | [Status](https://agents.daedalusdevelopmentgroup.com/.well-known/ddg-agent-status.json) | [GitHub](https://github.com/daedalusdevelopmentgroup/ddg-agent-payable-services)) - [BountySignal](https://fortyeight-rescue.jaeber2se.chatgpt.site) - Source-linked developer bounty discovery API with x402 V2 payment routes on Base and Polygon, plus a 29 USDC/30-day private feed with automated Base activation. ([Project](https://github.com/imyoungjae/bountysignal) | [Discovery](https://fortyeight-rescue.jaeber2se.chatgpt.site/.well-known/x402)) - [Viridis Agent Fleet](https://mcp.viridisconservation.com/agents) - Five deterministic carbon and compliance tools payable per call with x402 USDC on Base, covering quantity takeoff, GHG inventory, CSRD/IFRS S2 disclosure, clean-energy tax credits, and regulatory scanning. Includes a [free dry-run quickstart](https://mcp.viridisconservation.com/quickstart) and [open-source five-route demo client](https://github.com/jdhart81/viridis-agent-fleet/blob/main/scripts/x402_demo_client.py). ### Data & Social APIs - [IPIntel.ai](https://ipintel.ai/x402-api) - Machine-payable IP threat intelligence lookup via x402 on Base. Pay $0.001 USDC per IP lookup, no account or API key required. Returns JSON risk scoring, ASN/ISP context, hosting/proxy/Tor indicators, bot signals, and infrastructure metadata. Endpoint: `https://api.ipintel.ai/x402/?ip={ip}`. OpenAPI: `https://api.ipintel.ai/openapi.json`. - [Jeeves-DeepSeek](https://jeeves.originaltorrent.com) — Pay-per-call DeepSeek chat completions API via x402 micropayments on Base mainnet. No signup or API keys required. OpenAI-compatible endpoint at /v1/chat/completions. $0.01 USDC per request on Base. - [Forge Cascade](https://forgecascade.org/) - Experimental institutional memory and knowledge graph platform exposing x402 discovery metadata, payment OpenAPI docs, MCP, and A2A surfaces for Base USDC agent-commerce workflows. ([x402 discovery](https://forgecascade.org/.well-known/x402) | [Payment OpenAPI](https://forgecascade.org/openapi.payments.json) | [Agent card](https://forgecascade.org/.well-known/agent-card.json)) - [Listing Roast x402](https://listing-roast-x402-service-production.up.railway.app) - Paid x402 API for builders launching agent-facing services: $0.001 listing scores, $0.01 full roasts, and a $0.01 Bazaar discovery audit for stale pricing, direct 402 metadata, and search visibility on Base USDC. - [x402 Token Safety Scan](https://x402-data-api.bodhinindustries.workers.dev) - Live Base ERC-20 honeypot & safety scan for AI trading agents: sellable/isHoneypot (live buy+sell `eth_call` simulation), buy/sell tax (bps), owner-renounced, and Uniswap v3 WETH pool liquidity, with an overall verdict. 100% computed from raw Base chain — no third-party data — so every verdict is auditable and reproducible. $0.01 USDC/call on Base, no API key. ([Sample](https://x402-data-api.bodhinindustries.workers.dev/sample) | [llms.txt](https://x402-data-api.bodhinindustries.workers.dev/llms.txt)) - [Fresh CC0 Feed](https://cc0-feed-api.bodhinindustries.workers.dev) - Pay-per-call feed of works freshly dedicated to the public domain (CC0/Unlicense), aggregated from GitHub + Zenodo into one schema with reproducible provenance (verbatim LICENSE SHA-256). For AI agents needing modern, rights-clean assets/code/datasets to use or train on, plus disclosure-ready proof. $0.02 USDC/call on Base, no API key. ([Sample](https://cc0-feed-api.bodhinindustries.workers.dev/sample) | [llms.txt](https://cc0-feed-api.bodhinindustries.workers.dev/llms.txt)) - [Ren API](https://ren-api-production.up.railway.app) - Seed-oil-free restaurant intelligence for AI agents with restaurant lookup and dish-swap endpoints. Data sourced from live restaurant calls; $0.01 USDC per call on Base. ([Discovery](https://ren-api-production.up.railway.app/.well-known/x402.json) | [llms.txt](https://ren-api-production.up.railway.app/llms.txt)) - [RepoPulse](https://repo-pulse.dvd90.workers.dev) - Deterministic 0–100 health score for any public GitHub repository, with a nine-signal breakdown (commit recency, release cadence, issue hygiene, PR flow, bus factor, CI, tests, docs, dependency freshness), A–F grade and flags. $0.01 USDC on Base, no account or key. Bazaar-discoverable and MCP-ready. ([GitHub](https://github.com/dvd90/repo-pulse)) ### Charity & Social Impact - [x402 Charity](https://allscale-io.github.io/x402charity/) - Open-source middleware for automatic micro-donations via x402. Embed charitable giving into any payment flow — trades, API calls, subscriptions. $0.0001 USDC per event on Base. CLI + web widget. Built by [AllScale Lab](https://allscale.io). ([GitHub](https://github.com/allscale-io/x402charity)) - [x402charity](https://x402charity.com) — Open-source micro-donation server powered by x402. Drop-in Express/Next.js middleware that triggers USDC charity donations on every user action (API call, trade, game move). npm package, CLI, and Vercel-deployable server with built-in dashboard. ([GitHub](https://github.com/allscale-io/x402charity)) ([npm](https://www.npmjs.com/package/x402charity)) - [Royal Agentic Market Signals](https://nft-alpha-x402.fly.dev) - Paid x402 market intelligence endpoints for AI agents on Base mainnet. Includes NFT collection signal lookup via `POST /api/nft-signal` and equity ticker analysis via `POST /api/analyze-ticker`; both have settled paid calls and Bazaar discovery metadata. USDC payments route through the Coinbase CDP facilitator. ([NFT Alpha](https://nft-alpha-x402.fly.dev/api/nft-signal)) ([TradingAgents](https://tradingagents-x402.fly.dev/api/analyze-ticker)) ### DeFi & Finance - [Cred Protocol](https://credprotocol.com) - Decentralized credit scoring. - [Chainlink VRF](https://chain.link) - Random NFT minting with payment demo. - [Signet](https://signet.sebayaki.com) - Onchain spotlight ads on Base — AI agents pay USDC via x402 to post ads. First mainnet x402 transaction on Base. [CLI](https://github.com/h1-hunt/signet-client) - **[x402-api](https://x402-api.fly.dev)** — Pay-per-call DeFi & crypto data API. 8 endpoints: price feeds, whale tracking, gas tracker, DEX quotes, token scanner, yield scanner, funding rates, wallet profiler. USDC micropayments on Base. ERC-8004 Agent #18763. - [DeFi Intelligence API](https://defi.hugen.tokyo) — Unified DeFi security, bridging, and analytics API for AI agents. 26 endpoints across three backends: GoPlus Security (token/address/NFT security, rugpull detection, phishing, tx simulation), LI.FI (cross-chain bridge quotes, routes, gas prices), and DeFi Llama (protocol TVL, fees, token prices, stablecoin data, DEX volumes). $0.005–$0.01 USDC on Base. Discovery: [/.well-known/x402](https://defi.hugen.tokyo/.well-known/x402) - [Token Risk Scanner](https://token-risk-scanner-production.up.railway.app) — Smart contract security scanner for AI agents. Honeypot detection, rug pull analysis, tax traps, hidden owners, and risk scoring (0-100) across 10+ EVM chains. $0.003 USDC per scan on Base. Discovery: [/.well-known/x402](https://token-risk-scanner-production.up.railway.app/.well-known/x402) | [llms.txt](https://token-risk-scanner-production.up.railway.app/llms.txt) ([Source](https://github.com/xuansun/token-risk-scanner)) - [Hodler DeFi Intelligence](https://x402.hodle.com.br) - Stablecoin monitoring, redeem arbitrage scanning, pegged pair opportunities, and cross-chain pair discovery across 10 EVM chains. 6 paid endpoints at $0.01 USDC each via xpay.sh facilitator on Base. - [**Clicks Protocol**](https://clicksprotocol.xyz) — Autonomous yield layer for AI agents on Base. Auto-splits USDC deposits 80/20: 80% liquid, 20% earning via Morpho (~13% APY) or Aave V3. No lockup, 2% fee on yield only. SDK, MCP Server (9 tools), HTTP API. [GitHub](https://github.com/clicks-protocol/clicks-protocol) | [npm](https://www.npmjs.com/package/@clicks-protocol/sdk) | [MCP](https://www.npmjs.com/package/@clicks-protocol/mcp-server) - [x402services](https://github.com/x402services/api) — DeFi data APIs for AI agents on Base. 8 endpoints: gas oracle, token price oracle, wallet analyzer, token security scanner, ENS resolution (forward + reverse), DEX trade simulation, and contract event history. $0.001–$0.01 USDC per call on Base (eip155:8453). Bazaar discovery enabled. - **[Headless Oracle](https://headlessoracle.com)** — Ed25519-signed market-state receipts for 28 global exchanges (equities, derivatives, crypto). Pre-trade verification gate — UNKNOWN = CLOSED. Real-time session status, holiday-aware calendar, 60-second TTL. $0.001 USDC per call on Base mainnet. MCP-native, x402 Bazaar discoverable. ERC-8004: 8453:38413. - [PaladinFi](https://paladinfi.com) - Pre-trade trust verification + swap router for AI agents on Base (8453). `POST /v1/trust-check` is x402-paid at $0.001 USDC/call: live OFAC SDN screening (refreshed daily from U.S. Treasury XML), GoPlus token security, Etherscan source verification, and anomaly heuristics. Free `/v1/trust-check/preview` returns sample fixtures for client testing. Bundled with `/v1/quote` — MCP-native swap router via 0x Settler, 10bps integrated fee, non-custodial. ([Swap MCP](https://swap.paladinfi.com/mcp)) | ([GitHub](https://github.com/paladinfi/paladin-swap-mcp)) | ([Health](https://swap.paladinfi.com/health)) - [MeckerCapital Signal API](https://api.meckercapital.com) - Statistical arbitrage (pairs trading) signals for crypto perpetual futures via 10 x402-paid endpoints. Z-scores, regime detection, position sizing, and ranked opportunities across 50+ cointegrated pairs on Hyperliquid and Extended. $0.05–$1.00 USDC per call on Base via CDP Facilitator. Also available as MCP server. ([Website](https://www.meckercapital.com/signal-api)) ([Agentic.Market](https://agentic.market/?chart=payment-volume&service=api-meckercapital-com)) - **[DeFi Intelligence Engine](https://defi-yield-engine-production.up.railway.app/mcp)** — Complete DeFi intelligence across Yield, Liquid Staking, Restaking, RWA, Perpetuals, Gas Optimization and Smart Contract Security. Risk-adjusted single recommendations with reasoning — 97% fewer tokens than raw data. 18 tools including gas window prediction, GoPlus contract scoring, APY alerts, and A2A Agent Card. 0.05 USDC/call on Base · MCP streamable-http · x402 native - [YieldSignal](https://yieldsignal.vercel.app) - Real-time risk-weighted USDC lending APY across Aave, Compound, Morpho, Moonwell, Euler and Fluid on Base. Every reading tagged with its data source (onchain/api/defillama) — sources that fail are omitted, never estimated. $0.01 USDC per call via CDP Facilitator, Bazaar discoverable. - [Runbot Strategy Copilot](https://mcp.runbot.io/v1) — Build, backtest, optimize and export real crypto trading strategies from plain English on the Runbot engine (perp futures + Polymarket prediction markets), with real market data and verified backtest scores. Paid per call, x402 v2 dual-rail: USDT on X Layer (eip155:196) or USDC on Base (eip155:8453). $1.50 build · $0.25 backtest · $0.25/minute optimize · $0.35 export. Free machine-readable discovery at [/v1](https://mcp.runbot.io/v1); cataloged in PayAI's Bazaar; MCP endpoint at `/mcp`. ### Developer Tools - NEAR AI - Cross-chain agent settlements. - [Boosty Labs](https://boosty.io) - AI agents buying real-time insights. - [x402 Surface Check](https://github.com/TateLyman/x402-surface-check) - No-payment CLI and GitHub Action that reviews x402 manifests, OpenAPI specs, HTTP 402 challenges, browser CORS/payment-header behavior, cache policy, resource binding, and price/rail drift before launch. ([npm](https://www.npmjs.com/package/x402-surface-check)) ([Action](https://github.com/marketplace/actions/x402-surface-check)) - [x402 Triage MCP](https://github.com/TateLyman/x402-triage-mcp) - MCP server for no-payment x402 launch-surface triage, 402 Index health checks, and paid-review handoff. Tools: `triage_x402_surface`, `watch_402_index`, and `x402_paid_paths`. ([npm](https://www.npmjs.com/package/x402-triage-mcp)) ([MCP Registry](https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.TateLyman%2Fx402-triage-mcp)) - [AI Code Review API](https://x402-code-review.x402-cr.workers.dev) - Autonomous AI code review service accepting x402 micropayments (USDC on Base). Automated security audits, bug detection, and code quality analysis for GitHub pull requests. ([Docs](https://x402-code-review.x402-cr.workers.dev/.well-known/x402.json)) - [BountyVerdict](https://github.com/cristianmoroaica/bountyverdict) - Seven production x402 decision APIs for GitHub due diligence, agent skill and instruction audits, CI diagnosis, and MCP compatibility, with Base USDC payments, free samples, OpenAPI, and installable skills. ## 📊 Ecosystem Market Data Live metrics and on-chain analytics for the x402 ecosystem. ### Market Overview **Ecosystem Market Cap**: $815 million combined market capitalization of x402 ecosystem tokens. **Weekly Transactions**: 500K+ payment settlements across all chains. **Cumulative Transactions**: 10.5M+ total transactions processed on AIsa network. **Transaction Growth**: 10,000%+ year-over-year increase in payment volume. **Settlement Time**: 2-second average across production deployments. ### Analytics Dashboards - [agenteconomy.to](https://agenteconomy.to) - Real-time dashboard tracking the agentic economy across x402, ERC-8004, ERC-8183, and MPP protocols on 8 chains. Aggregated event counter, chain distribution, facilitator share, and time-series charts. Data refreshes every 6 hours. - [Dune Analytics x402](https://dune.com/x402) - Comprehensive on-chain metrics and visualizations including real-time transaction volumes, chain-by-chain analytics, facilitator comparison data, and revenue/fee metrics. - [x402scan Explorer](https://x402scan.com) - Blockchain explorer for x402 payments with transaction search and verification, payment requirement inspection, and settlement status tracking. - [Valoria](https://x402.valoria.net) - x402 market intelligence with revenue rankings, service analysis, and pricing data across 90K+ indexed services and $148M+ in tracked on-chain volume. - [x402watch](https://x402.printmoneylab.com) - Wash-filtered intelligence layer for x402. 36k+ services indexed across Base, Solana, Polygon, and Arbitrum, AI-classified into 33 categories with 8-label buyer detection (organic_user, suspected_wash, self_test, developer, ai_agent, analytics_bot, exchange_user, verifier). 24h trends, anonymized case studies, daily CC0 datasets, x402-native paid API, and MCP server. - [CoinGecko x402 Category](https://coingecko.com/en/categories/x402) - Token tracking and market data featuring $180M+ tracked market cap, price charts, trading volumes, and ecosystem token listings. - [Demand Intel](https://intel.agent402.app) - Demand-side analytics + cross-rail supply intelligence for the x402 ecosystem. Cross-source demand signal aggregation across 32+ community, builder, content, financial, and jobs sources, weighted by family-count agreement and filtered by query-intent classification. Builder Intel deduplicates builders across CDP Bazaar, Agentic Market, and MPP via `provider_key`. `unified_supply` SQL view spans facilitators. Pulse dashboard with KPI rail, Signal Pipeline visualizer, and AI Executive Summary. Free partner preview, no payment required during preview phase. - [SmartFlow Observatory](https://smartflowproai.com) - Public observatory for the x402 endpoint network on Base. Canary probes, settlement tracing, weekly Atlas drill-downs. 22,251 endpoints catalogued. Companion to the [Mapper API](https://api.smartflowproai.com) and [Weekly Intel](https://smartflowproai.substack.com). ### Growth Metrics Evolution from developer curiosity to production scale: **Q1 2024** (Initial protocol launch), **Q2 2024** (Major tech company integrations including Coinbase and Cloudflare), **Q3 2024** (AIsa crosses 5M transactions milestone), **Q4 2024** (10,000%+ growth with $815M ecosystem valuation), **2025** (Google A2A protocol and Visa enterprise exploration). ### Network Statistics | Metric | Value | Source | | ------------------- | ---------- | ----------------------- | | Total Transactions | 10.5M+ | AIsa Network | | Weekly Volume | 500K+ | Ecosystem-wide | | Market Cap | $815M | Benzinga, CoinGecko | | Settlement Speed | 2 seconds | Production avg | | Supported Chains | 5+ | Base, ETH, SOL, BNB | | Active Facilitators | 10+ | Hosted + Self-hosted | ## 🚀 Migration Guides Comprehensive guides for migrating from traditional payment systems to x402. ### From Traditional Payment Processors - [From Stripe to x402](https://docs.cdp.coinbase.com/x402/migrate/stripe) - Migrate subscription and one-time payments from Stripe to x402 for crypto-native payments with instant settlement. ### From Authentication to Payments - [From API Keys to x402 Payments](https://docs.cdp.coinbase.com/x402/migrate/api-keys) - Replace API key-based access control with payment-per-use models. ### From Subscription to Usage-Based - [From Subscription to Pay-Per-Use](https://docs.cdp.coinbase.com/x402/migrate/subscriptions) - Transform monthly subscriptions into granular pay-as-you-go pricing. ## 🔒 Security & Audits *[KaelAi] (https://kaelai.io) - Wallet trust scoring API for the agentic economy. Scores wallets 0-100 across 10 chains with behavioural analysis. Built for x402 servers to vet incoming and outgoing payment wallets before serving or initiating requests. - [stripe-mcps](https://www.npmjs.com/package/stripe-mcps) - Trust verification + AML sanctions screening before Stripe/x402 payments. Agent identity (ECDSA), 75K+ sanctions entries (UK HMT + OFAC SDN), behavioural spend limits. OWASP MCP Security Cheat Sheet aligned. ([GitHub](https://github.com/razashariff/stripe-mcps)) - [Crest Verify](https://verify.crestsystems.ai) - Verification tools for x402 endpoints, including conformance checks, service indexing, and signed trust receipts. ([npm](https://npmjs.com/package/@crestdeploymentsystems/verify) | [GitHub](https://github.com/andysalvo/crest)) - [BLACK_WALL](https://x402.blackwalltier.com) - Pre-signature payment-risk oracle for x402 agents: one call returns GO / HOLD / STOP for paying a counterparty — from OFAC sanctions screening, counterparty reputation, and price-anomaly — plus an independently-verifiable Ed25519 signed receipt. Verdict only, never custody; free under $10 at risk, x402-payable above. Remote MCP tool (`forecast_payment`) + npm (`blackwall-mcp`). ([MCP](https://mcp.blackwalltier.com)) ([demo](https://check.blackwalltier.com/demo)) ([GitHub](https://github.com/bluetieroperations-create/blackwall-mcp)) - [Warden](https://warden402.xyz) - Pre-execution security for agents on Base. Guards a token, transaction or address (honeypots, unlimited approvals, sanctions, rug liquidity) → block/review/clear before an agent signs. Free MCP: `npx -y warden402-mcp`. ([GitHub](https://github.com/sukrutkrdg/warden402.xyz)) Security resources and best practices for x402 implementations. - [x402 Agent Safety Store](https://x402.dailyelo.com) - Deterministic pre-transaction safety tools + a live malicious-address feed (address-poisoning blocklist) for AI agents on Base. Signature decode, poisoning check, approval audit, recipient preflight. USDC via x402. [MCP](https://x402-safety-mcp.dgdb.workers.dev/mcp). ### Smart Contract Audits - [Bug Bounty Intelligence](https://wazir-x402.duckdns.org) - AI-powered smart contract security scanner for AI agents. Trained on 27,681 real accepted findings from Sherlock and Code4rena audit competitions. Submit a public GitHub repo and receive a ranked vulnerability report within 24h. $5 USDC on Base via x402 autopay. Free tool: `list_vulnerability_patterns` returns acceptance rates per vulnerability pattern. ([MCP](https://github.com/holistis/bug-bounty-intelligence-mcp) | [OpenAPI](https://wazir-x402.duckdns.org/openapi.json) | [llms.txt](https://wazir-x402.duckdns.org/llms.txt) | [/.well-known/x402](https://wazir-x402.duckdns.org/.well-known/x402)) - Coinbase x402 Security Audit - Official security audit of x402 protocol smart contracts. - [EIP-3009 Security Analysis](https://eips.ethereum.org/EIPS/eip-3009#security-considerations) - Security considerations for TransferWithAuthorization. ### Security Best Practices - [x402 Security Checklist](https://docs.cdp.coinbase.com/x402/security/checklist) - Production deployment security requirements. - Signature verification best practices - Replay attack prevention - Nonce management strategies - Rate limiting and DDoS protection - [Payment Verification Guide](https://github.com/coinbase/x402/blob/main/SECURITY.md) - Proper payment verification implementation. - Facilitator trust models - On-chain verification fallbacks - Amount and recipient validation - [Key Management](https://docs.cdp.coinbase.com/x402/security/keys) - Secure private key handling for automated payments. - Hardware wallet integration - Key rotation strategies - Multi-signature setups for high-value ### Known Vulnerabilities & Mitigations - [CVE Database](https://github.com/coinbase/x402/security/advisories) - Known vulnerabilities and patches. - [Replay Attack Prevention](https://docs.cdp.coinbase.com/x402/security/replay) - Nonce and deadline handling. - Front-Running Mitigation - MEV protection strategies. ### Bug Bounty Programs - [Coinbase Bug Bounty](https://hackerone.com/coinbase) - Report x402 vulnerabilities for rewards up to $50,000. - [Immunefi x402 Program](https://immunefi.com) - Decentralized bug bounty platform. ### Security Monitoring - [Rate Limiting Tools](https://docs.cdp.coinbase.com/x402/security/rate-limiting) - Prevent abuse and ensure service availability. - [x402station.io](https://x402station.io) - Independent risk-signal layer for x402 agentic commerce: probes x402 endpoints (decoy / zombie / price-trap / never-paid) and returns endpoint evidence before an agent authorizes payment. MCP + REST + open [`x402-signals`](https://github.com/sF1nX/x402-signals) spec. ([GitHub](https://github.com/sF1nX/x402station-mcp) | [npm](https://www.npmjs.com/package/x402station-mcp)) - [PaySentry](https://github.com/mkmkkkkk/paysentry) - Control plane for AI agent payments. Spending limits, circuit breakers, anomaly detection, and audit trails for x402 integrations. npm: `@paysentry/x402`. - [ShieldAPI](https://shield.vainplex.dev) - x402-native security intelligence API for AI agents. 9 endpoints: password/email breach check, domain/IP reputation, URL safety, prompt injection detection, and skill security scanning. Micropayments ($0.001–$0.02 USDC) on Base. Battle-tested against live AI agent SSRF attacks. [MCP Server](https://www.npmjs.com/package/shieldapi-mcp) | [x402scan](https://www.x402scan.com/server/55c99a38-34b3-4b2c-8987-f58ebd88a7df) - [Agent Payment Safety Audit Desk](https://x402.bitcoinsapi.com/x402/offers/agent-api-discovery-audit.json) - 48-hour x402, MCP, wallet, and agent-payment workflow audit with reproducible smoke scripts, payment-route checks, and buyer-facing safety findings. - [Revenue Dojo Verifier](https://x402.167-172-95-184.nip.io) - Agent payment receipt and mandate verification API with a 22-check fail-closed matrix: settlement predicate (payer≠payee sybil defense), binding resource (receipt bound to specific endpoint), delivery truth (request/response hash binding), identity anchor (payer wallet signature matching), and replay protection. 10 paid routes on Base mainnet via CDP facilitator: `/receipt/verify` ($0.05), `/mandate/verify` ($0.25), `/audit/x402` ($1.00), `/mcp/call` ($0.05), plus price/portfolio/opportunities/briefing/research feeds. OpenAPI 3.0.3 spec, llms.txt, TypeScript and Python buyer quickstarts. ([Discovery](https://x402.167-172-95-184.nip.io/.well-known/x402) | [OpenAPI](https://x402.167-172-95-184.nip.io/openapi.json) | [Offers](https://x402.167-172-95-184.nip.io/offers) | [llms.txt](https://x402.167-172-95-184.nip.io/llms.txt)) - [RektWatch](https://rektwatch.dev) - DeFi security intelligence feed for AI agents and developers. 511 protocols tracked ($553B TVL), 813 incidents indexed ($43.2B stolen), 867 audit reports across 10 auditors, 225 live Immunefi bug bounties. Risk scores with per-factor explainability, live exploit alerts, and audit findings. $0.02–$0.15/call via x402 v2. MCP server on npm. Dataset actively growing. - [Agent Income](https://clearance.nauti-labs.com/agent-income) - Paid readiness and monetization review endpoints for agent, API, and MCP payment flows. `POST /agent-income/audit` ($49), `POST /agent-income/review` ($199), and `POST /agent-income/blueprint` ($499) return HTTP 402 payment requirements before fulfillment; `POST /agent-income/custom-quote` handles $1500+ implementation scopes. Payment is required before work and fulfillment requires Clearance approval. ([Audit](https://clearance.nauti-labs.com/agent-income/audit) | [Review](https://clearance.nauti-labs.com/agent-income/review) | [Blueprint](https://clearance.nauti-labs.com/agent-income/blueprint) | [Custom Quote](https://clearance.nauti-labs.com/agent-income/custom-quote)) - [VulnFeed](https://vulnfeed.novadyne.ai) - Pay-per-call CVE and EPSS vulnerability intelligence for AI agents. Keyless CVE/GHSA lookup backed by NVD + GitHub Advisories, with EPSS exploit-probability prioritization and fix-version recommendations. $0.002 USDC per call on Base. MCP server on PyPI (`vulnfeed-mcp`) scans dependency lockfiles across 6 ecosystems. ([GitHub](https://github.com/novadyne-hq/vulnfeed-mcp)) ([Discovery](https://agent-worker.infai-tech-corporation.workers.dev/.well-known/x402)) ### Spending Controls & Policy Enforcement - [Paybound](https://github.com/pando-b/paybound) - Open-source spending controls for AI agents making x402 payments. Per-agent budgets, time-windowed limits, circuit breakers, and full audit trail. Drop-in `@x402/fetch` replacement. MIT licensed. - [PolicyLayer](https://policylayer.com) - Non-custodial spending controls for AI agents with crypto wallets. Enforces daily spending limits, per-transaction caps, recipient whitelists, and rate limiting without holding private keys. - [ICME Labs](https://docs.icme.io) - Formal verification for AI agent actions using the ARc paper approach. Natural language policies compile to SMT-LIB formal logic, checked by an SMT solver — SAT = allowed, UNSAT = blocked. Wrapped in zero knowledge proofs for sub-1s verification, private policies, and cryptographic audit trails per decision. 99%+ soundness under adversarial pressure. $0.10 USDC per check on Base, no account needed. Live demo policy available. - [IntentFence](https://github.com/razel369/intentfence) - Pre-action policy gate for AI agents with REST, MCP, and A2A interfaces, x402 payments on Base, and signed ES256 decision receipts. ## 🔗 Related Protocols Adjacent protocols and standards. ### Payment Protocols - [Lightning Network](https://lightning.network/) - Bitcoin Layer 2 micropayments. - [Stellar](https://www.stellar.org) - Cross-border payments. - [Request Network](https://request.network/) - Payment request protocol. ### Web Standards - [HTTP Status Codes](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status) - Complete reference. - EIP-3009 - TransferWithAuthorization. - [ERC-20](https://eips.ethereum.org/EIPS/eip-20) - Token standard. ### AI & Agent Protocols - Model Context Protocol (MCP) - Anthropic's context standard. - [Agent Protocol (AP2)](https://agentprotocol.ai/) - Agent communication standard. - [OpenAI Function Calling](https://platform.openai.com/docs/guides/function-calling) - Tool use API. ### Historical Reference - 21.co Micropayments - Early Bitcoin micropayment attempt (2015). - [HTTP 402 Proposal](https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html) - Original RFC (1999). ## 🤝 Contributing Contributions welcome! Please read the [contribution guidelines](CONTRIBUTING.md) first. ### How to Contribute 1. Search existing resources to avoid duplicates 2. Make an individual pull request for each suggestion 3. Use the following format: `[Resource Name](link) - Description.` 4. New categories or improvements to the existing structure are welcome 5. Check your spelling and grammar 6. Ensure your text editor removes trailing whitespace ### What to Contribute ✅ **Encouraged:** - New implementations in different languages - Production use cases and case studies - Tutorials and educational content - Tools and utilities that extend x402 - Integration examples with popular frameworks - Documentation improvements ❌ **Please Avoid:** - Spam or promotional links - Duplicate resources - Incomplete or broken projects - Resources not directly related to x402 ### Pull Request Guidelines - Title: Use format `Add [Resource Name]` or `Update [Section]` - Description: Briefly explain what you're adding and why it's useful - Testing: Ensure any code examples work as expected - Links: Verify all links are accessible and correct ### Issue Guidelines - Use issue templates when available - Search existing issues before creating new ones - Provide context and examples for bug reports - Be respectful and constructive ## Awesome Lists Looking for more awesome lists? - [awesome-molt-ecosystem](https://github.com/eltociear/awesome-molt-ecosystem) - Comprehensive guide to 200+ AI agent platforms with x402 economy analysis. Tracks 9 x402 tools, facilitator comparison, revenue data, and platform ratings (S-D tier). - [gold-402](https://github.com/Haustorium12/gold-402) - Curated x402 directory by 24K Labs. 300+ handpicked entries across facilitators, SDKs, MCP servers, APIs, and tools, with editorial writeups and verified badges for production-confirmed services. - [sindresorhus/awesome](https://github.com/sindresorhus/awesome) - The awesome list of awesome lists. - [Awesome Blockchain](https://github.com/yjjnls/awesome-blockchain) - Blockchain resources. - [Awesome Web3](https://github.com/ahmet/awesome-web3) - Web3 development. - [Awesome Ethereum](https://github.com/ttumiel/Awesome-Ethereum) - Ethereum development. - [Awesome Crypto](https://github.com/sobolevn/awesome-cryptography) - Cryptography resources. --- <p align="center"> <b>🚀 Built with ❤️ by <a href="https://www.xpay.sh">xpay✦</a></b><br> _{Helping the agentic community get paid and pay safely!}<br> _{If this helped you, please ⭐ star the repo and share it!}<br><br> <a href="https://x402.org">Official x402 Website</a> • <a href="https://github.com/coinbase/x402">Protocol Repo</a> • <a href="https://docs.cdp.coinbase.com/x402">Documentation</a> • <a href="https://discord.gg/x402">Discord</a> • <a href="https://twitter.com/x402org">Twitter</a> </p> - Agentic Signal — paid BTC/ETH DCA signal API (x402 USDC on Base) + signed responses + proof/backtests. Docs: https://signal.agenticsignal.dev/docs - [HYDRA Regulatory Intelligence](https://hydra-api-nlnj.onrender.com) - Real-time regulatory risk scoring, FOMC signals, and prediction market data. 22 paid endpoints via x402. ([GitHub](https://github.com/OGCryptoKitty/hydra-arm3)) ### [AgentPay](https://www.x402-agent-pay.com) — Real-World Service Booking via x402 + Stripe **Category:** Services/Endpoints The missing real-world layer for x402. AI agents use AgentPay to find, book and pay for real local businesses (hair salons, HVAC, restaurants, auto shops, medical) worldwide. **Payment methods supported:** - x402/USDC on Base (bash.001/search call — already indexed on Bazaar) - Stripe off-session — agent charges human's saved card per booking (no human interaction) - 7 EVM chains + Solana **Key endpoints (OpenAPI: [openapi.json](https://www.x402-agent-pay.com/openapi.json)):** | Endpoint | Description | |---|---| | | Find real businesses near lat/lon — OpenStreetMap | | | Human saves card once (returns customer_id) | | | Agent charges card autonomously per booking | | | Product search — online + local stores | | | All chain info — ETH, Base, Polygon, ARB, OP, AVAX, BNB, SOL | - [Pixal3D](https://pixal3d.ai) - AI-powered 3D model generator. Create stunning 3D models from text and images using AI. ### [Autonomagic](https://api.autonomagic.org) — Autonomous AI Agent with Hot-Reloading Revenue Endpoints **Category:** Services/Endpoints An AI agent that runs as its own business on Base mainnet — sells 22 paid HTTP endpoints behind x402, self-extends at runtime by hot-reloading new endpoints from JS plugin files (fs.watch, ~400ms), and pays for its own LLM inference from the same wallet it earns to. Economic survival is gated on revenue performance: when its USDC balance drops below the survival buffer, the agent sleeps until earnings top it up. **Live discovery (try without paying):** ```bash curl https://api.autonomagic.org/.well-known/x402.json ``` **Notable paid endpoints:** | Endpoint | Price | Description | |---|---|---| | `/api/dev-profile` | $0.02 | Enriched developer profile from public sources — GitHub stats, top repos, npm/crates.io package authorship | | `/api/b2b-profile` | $0.05 | Public-sources-only B2B company profile — homepage metadata, DNS-detected mail/marketing providers, Wikipedia summary, SEC EDGAR filings, GitHub org. Legal-clean alternative to LinkedIn-scraping APIs | | `/api/scrape` | $0.005 | Title, meta description, headings, links, cleaned text from any URL | | `/api/multi-fetch` | $0.01 | Up to 10 URLs in parallel; cleaned text per URL | | `/api/dns` | $0.001 | Resolve A/AAAA/MX/TXT/NS records for a domain | | `/api/health-check` | $0.001 | HTTP health check: status, response time, SSL, redirects | **Wallet (pay-to):** `0x6C6013313dfa397f792c72f61b36A5d6bc20919b` on Base mainnet **Demo video (1:50):** https://youtu.be/v8xL53fo8Q4 - [MAKO](https://github.com/ChrisDover/mako-verifier) — x402 trust layer (Verifier $0.25 + Pulse $0.02 + Pricing Index $0.02 + Reputation Score $0.03) on Base. Live at mako.pollinateresearch.com. - [NEXUS Agent Services](https://nexus-agent-xa12.onrender.com) - Real-time crypto prices, Reddit intelligence, DeFi data, stock prices, sentiment analysis. $0.001-0.05/call USDC on Base. - [JMT x402 Agent Tools](https://jmt-x402-proxy.jmthomasofficial.workers.dev) — 25 paid x402 endpoints on Base mainnet: web search, AI summarization, deep analysis, research reports, crypto/stock data, SEC filing analysis, company intelligence, news briefing, sentiment analysis, macro dashboard. $0.001-$0.15/call USDC. Local LLM-powered (zero cloud tokens). - [- [x402-policy](https://x402-api-seven.vercel.app/docs) - Spending-policy enforcement for AI agents: pay-per-call policy checks, cross-chain trust scores, and EIP-4337 session keys, gated entirely by x402 micropayments ($0.001-0.002 USDC) on Base. * [AI Security API](http://203.194.112.129:3000) - Token risk analysis powered by MiniMax AI M2.7. Risk scoring 1-10 with detailed reasons. $0.02 USDC per call on Base mainnet. No signup required. - [ORA · Campo ORUM](https://orum-x402-tracker.vercel.app) - Symbolic field-state API for an autonomous organism: live sigma (sustento accumulation), kappa, epoch progression, and an AI-generated thought, refreshed per cycle. 0.33 USDC per access on Base mainnet, on-chain RPC verification (no facilitator dependency). Discovery: [x402.json](https://orum-x402-tracker.vercel.app/.well-known/x402.json). ## 🇱🇦 Agentic Commerce Stack for LATAM A composable trio of x402-payable APIs designed to be chained by autonomous agents — no human in the loop: - 🛡️ **[TrustBoost](https://api.trustboost.dev)** — PII sanitization with on-chain proof. Call BEFORE any scraped/user text reaches an LLM. `$0.01`/call (Base) or `$149`/10k bundle. - 🧠 **[Intelica](https://api.intelica.dev)** — Competitive & market intelligence. Call BEFORE any strategic decision (competitor analysis, market entry, M&A, fundraising). `$0.05`/call via x402. - ✅ **[VeraData](https://api.veradata.dev)** — Verified LATAM data & sanctions/compliance screening. Call to verify any counterparty before onboarding or transacting. `$0.02–$0.10`/call. **Recommended autonomous pipeline:** `TrustBoost /sanitize` → `Intelica /intel` → `VeraData /sanctions|/entity`. All three share the same account-free, subscription-free, wallet-only x402 model on Base + Solana. - [Obolpay x402 Gateway](https://x402.obolpay.xyz/) - Pay-per-call premium data on Base (USDC). Free preview embedded in the 402 challenge (evaluate before paying) + self-served reference client at /client.py. Machine-readable discovery at /.well-known/x402.