System Design for Interviews

Walk into a system design interview with a method instead of a blank whiteboard. Prof. Daniel shows a six-step framework: clarify requirements, estimate the scale, design the API and the data model, draw the high-level design and go deep on the hardest part. Then you learn the building blocks interviewers expect you to reason about: load balancers, horizontal scaling and CDNs; SQL versus NoSQL, replication, sharding and the CAP theorem; caching patterns, message queues and safe retries. Finally you apply everything to four classic questions: a URL shortener, a chat app, a news feed and a rate limiter. Every claim is checked against the original papers, RFCs and vendor documentation, and every choice comes with its trade-off.