Practical Backend Problem Solving Questions

Focuses on solving real world backend engineering problems where algorithmic correctness intersects with operational constraints. Example tasks include implementing rate limiting, designing cache eviction policies, processing and deduplicating event streams, parsing JavaScript object notation or comma separated values, detecting anomalies in logs, and ensuring idempotency of operations. Candidates should show how they reason about scale, latency, state management, fault tolerance, testing, and trade offs such as memory versus throughput or strong consistency versus eventual consistency. Interviewers expect pragmatic, correct solutions that consider instrumentation, failure modes, and how the design would evolve in production.