Webhooks

A failed delivery is retried on a fixed ladder — 1 min, 5 min, 30 min, 2 h, 6 h, 12 h, 1 d — for up to 8 attempts across roughly 1 d 20 h. An attempt with no next retry is the last one: after that the endpoint is auto-disabled and you are emailed.

Verify the signature on every request and treat the event id as an idempotency key — retries deliver the same event id, so a handler that has already processed it should answer 2xx and do nothing. Answer quickly and do the work asynchronously; a slow handler is indistinguishable from a broken one.

A manual redelivery never cancels the automatic schedule, and events you missed during an outage can be backfilled from the API rather than replayed by hand.