Reliability
Error Handling
Use HTTP status, the returned error message, and request identifiers where available. Never treat an initialization response as confirmed payment.
Retry carefully
Retry transient transport failures with backoff. Do not retry validation or permission failures unchanged.
Keep references stable
Reusing an idempotency reference prevents a network retry from creating another transaction.
Do not guess
When the API cannot retrieve a resource, show a clear unavailable state rather than fabricating data.