System Design Interview Guide
Prepare for system design interviews by turning ambiguous prompts into requirements, estimates, architecture decisions, and defensible trade-offs.
A repeatable interview method
- Clarify the problemIdentify users, core use cases, non-goals, and quality attributes.
- Estimate the systemUse rough traffic, storage, throughput, and latency estimates.
- Draw the critical pathStart with the simplest end-to-end flow.
- Defend the trade-offsExplain why each major component exists and what it costs.
- Test failure and scaleWalk through overload, partial failure, recovery, and consistency.