Backend Systems Engineer interview practice

High-concurrency distributed systems: caching strategy, idempotency, queues, and failure modes — with drill-downs on every scaling claim you make.

Topics this interview probes

Distributed systems Caching & stampedes Idempotency Message queues Database scaling Rate limiting

Design an idempotent payment API that can safely retry after a network timeout.
A cache stampede took us down yesterday. Walk me through prevention strategies and their trade-offs.
When would you choose a queue over a synchronous call, and what failure modes does that introduce?

The live interviewer generates fresh, role-tailored questions — and drills down when your answers are vague.