Outbound webhook delivery
Design the outbound webhook delivery system for a SaaS platform that notifies tens of thousands of customer endpoints of events (payment.succeeded, etc.) at ~50k events/sec. Requirements: at-least-once delivery with retries and exponential backoff, one slow or broken customer endpoint must not delay deliveries to everyone else, ordered delivery per customer where they want it, and customers must be able to verify a delivery is genuinely from us and replay missed ones.
What a strong answer looks like
Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts (data model, bottlenecks, consistency, failure modes) and name the trade-offs you are making.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
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.