These are the standard headers that should be included in HTTP requests to the API:
Content-Type: application/json X-Zip-API-Key: API Key supplied by Zip
The zipMoney API supports idempotency of refund operations in order to support retry on failure.
An "Idempotency-Key" header needs to be sent for each unique request. It is a good idea to use a UUID/GUID here to ensure no collisions of previous requests. If a request is to be retried the SAME value will need to be sent in the retry operation to let zip know that this is a replayed request.
This allows requests to be queued and replayed at a later time once any network or server issues are resolved without re-capturing or performing a refund twice.