Unverified50% confidenceFactExact time
The name x402 is derived from HTTP status code 402 (Payment Required), which was defined in the HTTP/1.1 specification but has long been reserved and unused.
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50%
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Long-term
Relevance
10/8/2026
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Related Claims
UnverifiedHTTP 402（Payment Required）是HTTP/1.1规范中最早定义的状态码之一，长期处于保留状态79% similarUnverifiedHTTP 429是HTTP协议中专门用于表示速率限制的状态码，服务器通常附带Retry-After响应头61% similarUnverifiedHTTP 403 (Forbidden) is the standard permission-denial status code, returned by the server when the requester lacks access rights to a resource.61% similarUnverifiedThe design philosophy of structured error codes originates from industry standards such as HTTP status codes and RFC 7807 (Problem Details for HTTP APIs).59% similarUnverifiedHTTP/2 is the HTTP protocol (RFC 7540) published by the IETF in 2015; its core innovations are binary framing and multiplexing, which resolve the head-of-line blocking problem of HTTP/1.1.59% similar
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