## Idempotent Requests
The `Authorization` and `Transfer` resources both have an `idempotency_id` field. Use this field to ensure the API Request is performed ***only once***.
Why is this important? We've all experienced a checkout page that hangs on a request or payment, and feared that if we refresh or submit the payment again, we'd be charged twice.
Finix removes this ambiguity with the `idempotency_id`. You or the user can generate a unique ID that can be included as an `idempotency_id` with the usual request payload. If anyone attempts a request with the same `idempotency_id`, the response will raise an exception.
By passing an `idempotency_id` in the body of your requests, you can be rest assured that when you create an `Authorization` or `Transfer`, the user will be protected from potential network issues.
`idempotency_id` is available on the following three endpoints:
- `/transfers`
- `/authorizations`
- `/transfers/{id}/reversals`

`idempotency_id` checks against previous requests made on the same endpoint.


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