How to Prepare for System Design Interviews
Having helped thousands of candidates pass their FAANG interviews, we've learned exactly what works.
In simple words: Preparation is spaced practice on core concepts, patterns, and full problems—not passive reading. Study a topic, then explain it aloud and sketch a design without notes. Use the other pages here as a checklist, not a substitute for timed mock interviews.
Quick prep plan (4 weeks)
- Week 1 — Core concepts: CAP, caching, sharding, load balancing, consistent hashing. One page per day; explain each in 2 minutes aloud.
- Week 2 — Patterns: scaling reads/writes, queues, rate limiting, real-time updates. Tie each pattern to one product you know.
- Week 3 — Full designs: Pick 5 problem breakdowns (URL shortener, chat, news feed, Uber, payment). 45-minute timed mocks with a whiteboard or paper.
- Week 4 — Delivery: Read the Delivery Framework page; practise clarifying requirements, estimating QPS, and naming trade-offs before drawing boxes.
Also revise your own notes: System Design, HLD, and back-of-envelope math.
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