What is the x402 (x402)?
Last verified 2026-05-31x402 is an open payment standard launched by Coinbase on 6 May 2025 that carries native stablecoin payments over HTTP by reviving the dormant 402 "Payment Required" status code. It lets apps, APIs and AI agents pay per request without accounts or API keys. Settlement happens on-chain through facilitators (Base, Polygon, Arbitrum, World, Solana), with the first "exact" scheme using EIP-3009. It launched with AWS, Anthropic, Circle and NEAR, is licensed under Apache 2.0, and its specification has since moved to the x402 Foundation.
Key facts
| Author / steward | Created by Coinbase; specification stewarded by the x402 Foundation |
|---|---|
| Announced | 2025-05-06 |
| License | Apache 2.0 |
| Governance | Launched by Coinbase; the specification was transferred to the x402 Foundation (the coinbase/x402 repository is now a development fork); homepage x402.org |
| Scope | An open payment standard for internet-native payments built on the HTTP 402 (Payment Required) status code; transport-agnostic, designed for humans, apps and AI agents |
| Transport | HTTP (402 status code and payment headers); transport-agnostic, with MCP and A2A representations |
| Payment | On-chain stablecoin settlement via facilitators; first scheme exact (EIP-3009 gasless ERC-20); supports Base, Polygon, Arbitrum, World and Solana |
| Maturity | stable |
What makes it distinctive
- Launched by Coinbase on 6 May 2025
- Revives the dormant HTTP 402 Payment Required status code for native payments
- Launched with collaborators AWS, Anthropic, Circle and NEAR
- On-chain settlement via facilitators; exact scheme uses EIP-3009
- Specification transferred to the x402 Foundation; licensed under Apache 2.0
Adoption
Frequently asked questions
What is x402?
An open standard from Coinbase, launched 6 May 2025, that sends stablecoin payments over HTTP using the 402 Payment Required status code.
Does x402 only work with crypto?
Settlement today is on-chain stablecoins via facilitators; the protocol is transport- and asset-extensible by design.
How does x402 relate to AP2?
Google AP2 extends crypto payments through the A2A x402 extension, so the two interoperate.