Test the full lifecycle
Validate successful checkout, failed payment, duplicate client attempts, delayed confirmation, refund, partial refund, cancellation, fulfillment, and webhook retry behavior that applies to your integration.
Use idempotency
Where the API or integration contract provides idempotency controls, use them consistently so a retried network request does not create an unintended duplicate side effect.
Reconcile from authority
Confirm that your internal system can recover from a missed frontend redirect by reading canonical MemberConsole state or receiving the durable merchant event.
Go live deliberately
Move production traffic only after domains, credentials, event endpoints, merchant scope, products, and expected customer return paths have been verified.