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
- coinbase/x402 (GitHub)
- x402-rs (Rust Facilitator & SDK)
- x402 TypeScript SDKs
- x402-Solana (Community)
- Pipegate (x402 + Payment Channels)
- 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.
- 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
- 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: 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
- 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.