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Idempotency

Retry safely: the same request with the same key never sends twice.

Add an Idempotency-Key header (1–256 characters) to any POST. For 24 hours, repeating the same request with the same key returns the first response instead of doing it again, with an idempotent-replayed: true header.

Idempotency-Key: order-1042-receipt
  • The key is matched with the method, path and body. The same key with a different body returns 409 idempotency_conflict, and so does a request whose first try is still running.
  • Error responses (4xx) are replayed too. Server errors (5xx) and rate limits (429) aren't stored, so you can retry them with the same key.
Tip
Build the key from something unique in your system, such as order-1042-receipt, rather than a random value per attempt.
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