Idempotency is a property where an action will result in the same outcome, regardless of how many times you run that action. In payments, idempotency is particularly important because it eliminates the risk of accidentally charging someone twice.

In order to prevent unintentional duplicate API requests, Moov includes an idempotency key (X-Idempotency-Key) in the header for the following endpoints:

You are responsible for generating a version 4 UUID idempotency key and setting it in the header. The idempotency key will not expire.

Moov will flag any transfer with the same idempotency key as a duplicate. If you try to create a transfer with the same idempotency key twice, your second attempt will result in a 409 error response indicating that a transfer was previously created with that idempotency key.