x402: An open protocol for internet-native payments backed by Coinbase

x402 is presented as an open, neutral standard for internet-native payments that lets clients and servers pay each other directly over HTTP. The page says servers can require payment with a single line of middleware, and that an unpaid request receives an HTTP 402 response prompting the client to pay and retry. It states that x402 has zero protocol fees, requires no accounts or personal information, and is not tied to any specific network. According to the FAQ, the protocol is production-ready, has processed millions of transactions, and has been audited for security.