COINBASE'S X402 EXPLAINED: CRYPTO PAYMENTS OVER HTTP

Summary from the TLDR Crypto newsletter

Coinbase's x402 revives the long‑dormant HTTP 402 status code as a native payment layer for the web, enabling APIs, apps, and AI agents to request and receive instant stablecoin payments directly over HTTP. Clients encountering a 402 response include payment details in an X-PAYMENT header and resubmit the request. Once on‑chain settlement is confirmed by a facilitator, the server fulfills the resource and returns an X-PAYMENT-RESPONSE. By embedding programmable, micropayment‑friendly transfers into standard HTTP without redirects, plugins, or centralized processors, x402 positions itself as a foundational protocol for autonomous, machine‑driven commerce.