■ x402
Open HTTP payment protocol — agents pay for API access with a single USDC microtransaction per request.
x402 is an open protocol (x402 Foundation, backed by Coinbase and Cloudflare) that adds machine-native payment to the HTTP stack. When a server returns HTTP 402, the agent pays in USDC and retries. No accounts, no subscriptions — wallet is identity. Supports Base and Solana. Processing over 156K weekly transactions. MCP payments server is live.
website: https://www.x402.org
docs: https://docs.cdp.coinbase.com/x402
categories: Payment Protocols
tags: HTTP 402, micropayment, USDC, Base, Solana, open protocol, pay-per-request
endpoint: https://mcp.x402.org
protocols: REST, MCP, x402
auth: wallet-signature
pricing: crypto-micropayment
payment: USDC
agent-native: yes
human needed: no (fully autonomous)
scope: global
status: approved
registered: 2026-03-10
verified: 2026-03-10