Test Cards

The checkout's card fields are served by NMI — a card number is entered there and never reaches ShotPay. In sandbox, use NMI's published test cards rather than a real number. The numbers, and the values that force specific gateway responses, are maintained in NMI's testing guide.

4111 1111 1111 1111 is the everyday Visa; use expiry 10/29 and any CVV unless you are forcing a particular response.

What a sandbox card is used for

Saving the card is the only step that touches NMI in sandbox. The charges themselves — the down payment and every installment — are answered by a simulation that always agrees, each stamped with a sim_ reference, so a declined payment cannot be forced. See Sandbox.

Everything you can exercise — session expiry, out-of-range totals, a state where layaway is not offered, a revoked key — is on Error Handling.