Async APIs for Long Running Work

A partner requests an account export. The server answers 202 Accepted.

Two hours later, the partner still does not know whether the export started, is running, failed, or finished. It also needs to know whether to retry or cancel.

202 Accepted is not a complete asynchronous contract. It says only that the request was accepted for processing. The response must name the resource through which the caller observes that processing.

Slow work becomes a resource with identity, states, a result or named failure, cancellation behavior, and an expiry.