payment receipt

The Internet-Draft behind MPP defines a Payment-Receipt header field carried on a successful response. It holds an encoded object whose status is always success, together with the payment method used, the settlement time and a method-specific reference. The draft requires that servers do not return the field on error responses.

x402 defines its receipt in an extension rather than in the core. There a receipt is a signed statement returned by the resource server on success, confirming that payment was received and service was delivered. It names the network, the resource paid for, the payer and the time it was issued, with the transaction hash where one exists. The extension pairs it with an offer — a cryptographic commitment by the resource server to the terms it presented.

What a receipt is evidence of is decided by who issues it. It is made by the party that took the payment and records what that party says happened, which is what reconciliation needs and is not the same thing as an independent record. A settlement is a transfer on a public network that anybody can look up afterwards. A reading of an endpoint is a capture somebody else took at a stated time. A receipt is neither of those.