Alert routing and deduplication
Design the alerting and notification routing layer that sits behind a metrics platform for 2,000 engineering teams. Rule evaluators across multiple regions fire ~30k alert state-changes/min during a large outage (normally ~200/min). You must deduplicate identical alerts from redundant evaluators, group related alerts into a single notification, route to the right on-call via escalation policies, and never drop or double-page. Design state management, dedup, grouping/throttling, and delivery guarantees.
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.
Clarify4:00 left
Estimate4:00 planned
Design11:30 planned
Deep dive9:30 planned
Failure6:00 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.