A 45-Minute System Design Framework

System design interviews reward structured thinking over memorized architectures.

The 45-minute timeline

1. Requirements (5 min) — functional vs non-functional, clarify scope
2. Estimation (5 min) — QPS, storage, bandwidth back-of-envelope
3. High-level design (10 min) — boxes and arrows, data flow
4. Deep dive (15 min) — database choice, caching, bottlenecks
5. Wrap-up (10 min) — trade-offs, monitoring, failure modes

Where to practice

Browse our System Design section for questions like URL Shortener with full walkthroughs.