An open HTTP standard that enables AI agents and web services to pay instantly using stablecoins (e.g., USDC). Built for pay-per-use, micropayments, and autonomous agent commerce.
X402 leverages the HTTP 402 "Payment Required" status to embed on-chain stablecoin payments into web interactions. With lightweight middleware, developers can enable pay-per-request monetization, instant settlement, and agentic transactions without API keys or subscriptions.
Run a $0.01 USDC demo: observe an HTTP 402 response that provides payment parameters (amount, token, payTo, network). Client signs an authorization (EIP-712), submits payment, and the resource unlocks instantly.
X402 is an open, chain-agnostic payment protocol (originating from Coinbase Developer Platform). Servers reply with a structured HTTP 402 payload (e.g., maxAmountRequired, payTo, asset, network, expiresAt, nonce, paymentId). Clients sign the payload (EIP-712), submit authorization, and the server verifies/broadcasts settlement then fulfills the request.
Defines a standard 402 payment payload so developers can add pay-per-request monetization with minimal code (middleware examples available). Works with existing web stacks.
Primarily uses stablecoins (e.g., USDC) and Layer-2 rollups (like Base) for near-instant finality and very low fees—making micropayments practical.
Designed for autonomous agents: agents can receive a 402 response, auto-sign, pay, and retry—enabling fully autonomous tool use and pay-per-use APIs.