A subscriber to your webhooks needs to know how long they have to fix an outage, and the answer is usually undocumented.
documented, on the same page as the payload schema:
attempt 1 immediately
attempt 2 +30 seconds
attempt 3 +2 minutes
attempt 4 +10 minutes
attempt 5 +1 hour
attempt 6 +6 hours
attempt 7 +24 hours
then the endpoint is disabled and you are emailed
we consider any 2xx a success and everything else a
failure. a timeout is 10 seconds.
The total window matters more than the individual intervals — a subscriber planning their own maintenance needs to know they have thirty-one hours rather than thirty minutes. Stating what counts as success is the other half, because a subscriber returning 302 or 204 needs to know whether that is acceptable.