Princeps Idempotency

The Princeps Idempotency extension allows certain requests to contain an Idempotency Key, preventing duplication of requests where only one instance should exist.

This works by introducing an Idempotency-Key header to certain requests, where, if a duplicate is provided (and the older request has completed), the response provided for that request will be re-sent. If the older request has not yet completed, a 409 will be returned to the sender.

As an extension, this service cannot operate by itself and requires a supported Princeps application to attach to. Only some applications support this extension out-of-the-box but a Change Request may be requested to extend support for this extension as required.