Payments processed twice from webhooks
You receive payment webhooks from a third-party provider. Your handler records the payment and ships the order. The provider retries any webhook it doesn't get a 2xx for within 10s. Starting at 12:00, a slow downstream made your handler take 12–15s; afterward, ops finds duplicate shipments and duplicate ledger rows for a subset of payments. Dashboards: handler error rate flat (it returns 200, just slowly), order/shipment volume elevated. How do you triage, stop the duplicate side-effects, and reconcile?
What a strong answer looks like
Stop the bleeding first (mitigate), then form hypotheses from real signals. Separate root cause from symptom, communicate status as you go, and close with what prevents a repeat.
0:00 of about 35 min
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.