Unverified50% confidenceFactExact time
The custom HTTP headers PAYMENT-REQUIRED and PAYMENT-SIGNATURE are the data carriers of the x402 protocol; an ordinary browser or unadapted client will only see the 402 and JSON response body and will not mistakenly trigger a payment.
1
Sources
50%
Confidence
Long-term
Relevance
10/19/2026
First Seen
Sources
Related Entities
Related Claims
UnverifiedThe 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.76% similarUnverifiedIn x402 v2, the PAYMENT-REQUIRED header of the 402 response contains base64-encoded payment terms; in x402 v1, the payment requirements are provided as JSON in the response body for compatibility with older clients.74% similarUnverifiedThe x402 protocol reuses HTTP's 402 Payment Required status code, letting the server declare in its response the amount, asset, and settlement chain required to pay for the call, on which basis the client completes signing and retries.72% similarUnverifiedHTTP 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69% similarUnverifiedIn most webhook protocols, the HTTP status code indicates "whether this delivery was accepted", not "whether the business has finished processing".68% similar
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