Webhook Retry Calculator

With base delay b, multiplier m and cap c, the delays are min(b·m^i, c); their sum is the geometric series b(m^k − 1)/(m − 1) over the k attempts before the cap, plus (attempts − k) × c afterwards. Exponential backoff grows geometrically until it hits the cap and then becomes linear, so the total window is a geometric sum plus a flat tail. Full jitter randomises each delay uniformly, which halves the expected wait and — more importantly — spreads a synchronised retry storm out over the delay window instead of concentrating it in one second.

A retry schedule without jitter is a self-inflicted denial of service on the consumer: every failed delivery retries in lockstep, so the recovering endpoint is knocked over again by your own traffic.

This calculator takes 7 inputs: Base delay before the first retry, Backoff multiplier, Maximum attempts, Delay cap per attempt, Full-jitter range applied to each delay, Per-attempt delivery success, Events failing in the same instant. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Enough to ride out a normal outage and no more — typically six to ten attempts spread over a few hours to a day, then a dead-letter queue with an operator-visible replay. Retrying for a week hides the failure, ties up delivery workers and eventually replays events the consumer no longer has context for.