An open payment protocol that Coinbase authored and open-sourced in May 2025. It revives the dormant HTTP 402 "Payment Required" status code so a payment can be attached to an ordinary web request, settling in USDC in a single round trip — no account, no API key, no subscription.
HTTP 402 was reserved for payment in the original specification and then left unused for three decades. x402 gives a server a way to answer a request with "pay me", and the client a way to pay and retry.
The payment travels with the request. There is nothing to sign up for, no key to provision and no subscription to cancel, which is what makes it usable by software that was written this morning.
Coinbase reported 69,000 active agents, 165 million transactions and around $50 million of cumulative volume by late April 2026. These are the protocol author’s own figures and are not independently audited.
x402 sits under Linux Foundation governance, with Google, Visa, Mastercard, Stripe, AWS and Circle among the named backers.
Cloudflare’s press release does not mention x402 or Coinbase. The connection comes from Cloudflare’s engineering blog and third-party reporting, and no partnership between the two companies has been announced.
A way for a website to charge for a single request instead of selling you a subscription. The server answers "payment required", the client attaches a small stablecoin payment and asks again, and the whole thing completes in one round trip with no account involved.
Coinbase authored it and open-sourced it in May 2025. It now sits under Linux Foundation governance, with Google, Visa, Mastercard, Stripe, AWS and Circle among the named backers.
Coinbase reported 69,000 active agents, 165 million transactions and around $50 million of cumulative volume by late April 2026. Those figures come from the protocol’s author rather than from a neutral auditor, and should be read that way.
HTTP 402 "Payment Required" was reserved in the original HTTP specification and then never implemented by anyone for about thirty years. x402 finally gives it a meaning.
No such partnership has been announced. Cloudflare’s press release does not mention x402 or Coinbase at all — the connection comes from Cloudflare’s engineering blog and from third-party reporting.