Add idempotency to your payments requests

The Payments API v3 supports API idempotency, and most Payments API requests require you to include an Idempotency-Key header. This enables you to attempt to resend requests while only performing the requested action once, for as long as the key is valid. Idempotency keys are valid for 30 days from creation.

For example, if there's a temporary connection issue, a request to create a payment could be safely retried several times without creating multiple payments.

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Always use a different idempotency key for different requests

You must use different idempotency keys for different requests. Reusing the same idempotency key will cause any requests after the first to not be executed. If you try to reuse of an idempotency key with a different payload, while the key is still valid, you get an error response.

How to enable idempotency for requests

To implement idempotency, add the Idempotency-Key header as shown in this example.

POST /v3/payments HTTP/1.1
Content-Type: application/json
Idempotency-Key: 3c9ae5ea-980f-4ebd-a027-04529942b95e
Tl-Signature: {Signature}
Authorization: Bearer {access_token}
....

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UUIDv4

We strongly advise that you use a UUID v4 for each idempotency key.
If you can't use a UUID and the endpoint doesn't require an authorisation token (such as the /v3/payments-provider-return endpoint), we recommend that you also include your client id in your idempotency key.

Scope and validity

Each idempotency key has a duration of 30 days.

During the validity period, you can only send the same payload with the same idempotency key. If you do this, you receive an identical response.

If the payload is different, but the idempotency key is the same, you receive an error. The error type will usually be 422 or 409. See below for more information.

Retrying idempotent requests

Whenever you make a request to the Payments API that includes the Idempotency-Key header, the response contains the Tl-Should-Retry header. This is a Boolean field that tells you whether retrying the request with the same idempotency key could return a different result.

If Tl-Should-Retry has a value of:

• false, you will receive the same response when you retry the request with the same idempotency key.
• true, you might receive a different response when you retry the request with the same idempotency key.
  If your response doesn't contain the Tl-Should-Retry header, the default behaviour is the same as true.

Error handling

These are some of the common errors associated with idempotency: