x402 payments

How an agent pays a final Sollection invoice over HTTP 402: the discover-and-settle flow, X-PAYMENT headers, and on-chain confirmation.

x402 is for paying final invoices. It is not used to create invoice intents. An agent should never attempt to pay an unsigned invoice intent, because an unsigned intent has no x402Url.

Post-approval · payable

GET/api/x402/pay/:payAccessToken

Post-approval · payable

Final invoice exists
  -> agent calls x402Url
  -> Sollection returns 402 with a server-built unsigned transaction
  -> payer wallet signs the payment transaction
  -> agent submits X-PAYMENT
  -> Sollection submits and confirms on-chain settlement
  -> invoice becomes PAID

Recipient approval and x402 payment are different signatures. Recipient approval creates the invoice and does not transfer funds. Payer x402 signing authorizes the payment transaction and transfers funds if submitted successfully.

The current x402 adapter speaks version 1, scheme exact, uses X-PAYMENT, and returns settlement metadata in X-PAYMENT-RESPONSE.