System Design Interviews

Coming soon: the clips for this path

The concepts below are the order this topic will be taught in. There is nothing to watch yet. Know a video that explains one of them well? Suggest it.

1. 01The answer framework. Requirements → estimates → high-level design → deep dives. Structure beats trivia: the interviewer is grading how you narrow an open problem.
2. 02Back-of-the-envelope estimation. Requests per second, storage per year, bandwidth. Two minutes of arithmetic decides whether the design needs one machine or a thousand, and every later choice follows from that number.
3. 03The scaling levers, in order. Vertical then horizontal, load balancers, CDNs, caching. Reach for them in the order that buys the most for the least new failure surface.
4. 04Sharding and what it costs. Splitting data across machines buys throughput and sells you joins, transactions and a shard key you cannot easily change.
5. 05Consistency trade-offs. CAP in practice: when eventual consistency is fine and when it never is. The answer is about the product, not the theorem.