Some API requests can't finish in time for a single HTTP response. Generating a report, transcoding a video, running a batch import — these take seconds or minutes, far longer than any client should hold a connection open for. If you try to do this work inside a normal request, you'll hit gateway timeouts, frustrated clients retrying half-finished jobs, and load balancers killing connections at 30 or 60 seconds. The fix is a well-established HTTP pattern: accept the work, hand back a receipt, an