Activepieces sync webhook 408 at 30 seconds: use Sume async

Behind an Activepieces /sync webhook, call Sume with the default async mode, not sync. Async returns 202 with the job envelope and a job id straight away, so your Return Response step answers well inside Activepieces' 30 second window and the render finishes on its own.

Activepieces facts are from its limits page; Sume facts from Jobs and results, both read 2026-09-30.

When does Activepieces return 408?

The limits page sets the sync webhook response timeout at 30 s on Cloud. For URLs ending in /sync, a run that fails answers at once with HTTP 500. HTTP 408 is returned only when the run never produced a response within the timeout, which covers a flow still running or one that finishes without a Return Response step.

Why is Sume's sync mode not the fix?

Sume's sync mode waits up to wait_timeout_seconds (max 30) for a terminal state, so on a long render it can use the whole Activepieces window and still return a non-terminal job. The mode never changes how long the job takes to run.

What if a sync call returns an unfinished job?

Poll, do not resubmit. A non-terminal sync response still carries the job id, status_url and a sync.timed_out flag; a repeat submit must reuse the same Idempotency-Key.

What does the flow look like?

Trigger on /sync, create the Sume job in async mode, and Return Response with the job id and status_url. The caller, or a later flow, reads the result from there. See the 10-minute run limit for pausing a long run.