x402
Paying for a request with the HTTP 402 status code, so an agent can settle a charge inline.
Why an agent cares
It is the only agentic-payment approach with real transaction volume, and it turns metered access into something an agent can handle without a human. The signal is a response to a request we do not make, not a document we can fetch.
Why we do not score it
A crawl sees a 402 only by attempting a paid request. Scoring that would mean initiating payment flows on other people's sites, which the container will not do.
Adoption
Early production. Several independent organisations run it in production, though it is still niche on the open web.
Direction of travel: ▲ rising, as at .
AWS shipped GA support in CloudFront and WAF, and governance moved to a Linux Foundation foundation with 40 members (Jul 2026). Chainalysis measured 100M+ transactions but attributes much of the growth to meme-coin farming.
Specifications
| Document | Revision | Kind |
|---|---|---|
| x402 | living | specification |
Last re-read against the published documents: .