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✅ Settle the Payment

After a successful proximity exchange, preserve the complete request, response, session transcript, and reader key in an Iso18013PresentmentRecord. Submit that record to the terminal backend; the records server is the authority that verifies it and moves funds.

Commit only a completed presentment​

The POS converts a successful reader outcome into a presentment record. A missing response or a non-zero status becomes an error path instead.

Treat settlement as the decision point​

The UI calls commit() only after it has a complete presentment record. It shows approval only after the backend returns a transaction ID; transfer, cancellation, and settlement errors all become a declined sale with a reason the cashier can act on.

  • This code block commits the record, creates an approved receipt state only from the server's transaction ID, and maps cancellation, transfer, and server errors to a declined state.

Never settle based solely on claims extracted in the terminal UI. The server must verify the issuer and device signatures, match the device-signed payment data to the reserved transaction, and ensure the transaction has not already been committed.