Idempotency

Idempotency protects financial write operations from accidental duplication.

http

Idempotency-Key: payment-order-4832

If a client times out after submitting a payment, it can retry with the same key.

Rules

Reuse a key only for the same logical operation.
Do not reuse a key with a different request body.
Generate the key before sending the request.
Keep it stable across network retries.