Curated resources for the x402 ecosystem: specs, repos, standards, and community. Contributions welcome via pull requests.
x402 is an emerging open standard from the Coinbase ecosystem focused on safer, more composable authorization and transaction flows. This list tracks authoritative resources and adjacent standards commonly used alongside x402-style flows.
- x402 Official Website
- x402 Whitepaper (PDF)
- x402 Developer Docs Portal
- Coinbase Announcement – Introducing x402
- GitHub repo — issues, proposals, and reference materials
- Cloudflare Announcement of the x402 Foundation
- x402Scan - Analytics and overview of the x402 ecosystem.
- x402station - Analytics and monitoring platform for x402 services with real-time insights and performance tracking.
- x402 Ecosystem Directory
- Coinbase Hosted Facilitator (Base) -- Supported Networks
- PayAI Facilitator & Supported Networks
- thirdweb Facilitator & Supported Networks
- Corbits Faremeter Facilitators & Supported Networks
- coinbase/x402 (GitHub)
- x402-rs (Rust Facilitator & SDK)
- x402 TypeScript SDKs
- x402-analytics (NPM) - Analytics wrapper for x402 payments with monitoring and insights.
- x402-Solana (Community)
- Pipegate (x402 + Payment Channels)
- thirdweb/x402 (Github)
- Faremeter (Typescript Facilitator, Middleware, and Examples)
- x402-dotnet (Community)
- MCPay (Build and Monetize MCP servers. SDK, Infrastructure and Examples)
- x402-mcp package (Vercel)
- x402-rails (QuickNode) - Ruby gem for integrating blockchain micropayments into your Ruby on Rails application
- x402-payments (QuickNode) - Ruby gem for generating signed payment HTTP headers and links using the X402 protocol
- ERC-3009 — Transfer With Authorization: meta-transaction transfers using EIP-712 signatures, enabling gasless and recipient-submitted transfers.
- EIP-712 — Typed Structured Data Hashing and Signing: canonical typed signing used by modern wallets.
- EIP-2612 — permit for ERC-20: approvals via signatures; often complementary to authorization-based flows.
- ERC-4337 — Account Abstraction (AA): smart account architecture that pairs well with authorization patterns.
- ERC-3009 Forwarding: forwarding contract extending meta-transactions with EIP-721 signatures to any ERC-20 on any network
- QuickNode – How to Implement a Crypto Paywall with x402
- Circle Blog – Autonomous Payments using Circle Wallets, USDC, and x402
- x402 Quickstart for Sellers
- x402 Quickstart for Buyers
- MCP Server with x402 Guide
- Base AgentKit – Building Autonomous Agents with x402
- Vercel x402 MCP SDK Announcement
- How to Get Started with x402 on Solana – Official Solana guide for integrating x402 payments on Solana networks.
- QuickNode Video Paywall Demo
- Hyperbolic x402 Chat API (LLM Pay-per-Request)
- Pinata – Pay to Pin on IPFS with x402
- Pinata 402-server (Code)
- Pinata – Monetize AI Hardware (Jetson) with x402
- Pinata jetson-x402 (Code)
- x402 Example Gallery (GitHub)
- x402 Analytics Examples - Practical examples demonstrating x402-analytics usage with buyer and seller implementations.
- x402 Starter Kit – by Nader Dabit – Simplest starter kit for building and deploying x402 APIs quickly.
- x402: Building Tools for AI agents, Demos, and Use-Cases
- x402: Revolutionizing How AI Agents Pay for Services
- x402: Building dynamic tools for AI agents, demos, and use-cases.
- Agent Bootcamp with x402 I Lincoln Murr
- Eliza Social Club: The latest with x402 and autonomous agents
- x402 Explained in 42 Seconds – Yinka – Short video explainer by Yinka introducing the x402 protocol.
- Customize Your x402 Paywalls – Koha – 41-second video by Koha showing how to set up and customize x402 paywalls.
- Building Apps and Agents with x402 – EigenCloud Broadcast – X broadcast with Dhaiwat and EigenCloud on building AI agents using x402.
- x402 Explained in 100 Seconds – Nader Dabit – Nader Dabit breaks down x402's purpose and shares key developer resources.
- Cognitive Revolution Podcast – "402 Payment Required"
- The Index Podcast – Coinbase's x402 & AI Agents
- RelayMag – x402 Handshake Explainer
- Boosty Labs Blog – AI Agents That Pay Their Own Bills
- a16z – The Month Fintechs Embraced Stablecoins (mentions x402)
- Add high-signal links: specifications, reference implementations, deep-dive posts, audits, and example apps.
- Prefer primary sources and canonical specifications.
- Submit a PR with a concise description; group items under existing sections when possible.
This list is offered under CC0; see upstream specs for their respective licenses.