1System Design Interview Framework— The meta-skill: how to approach any system design problem
2Back-of-Envelope Estimation— Estimate scale, storage, and bandwidth confidently
3Load Balancing— Distribute traffic across servers for reliability
4Caching— Speed up reads with Redis, CDN, and cache strategies
5Database Design— SQL vs NoSQL, sharding, replication, indexing
6System Design Cases— Design Twitter, YouTube, Uber, and 20+ real systems
7Mock Interviews— Full timed practice rounds with AI feedback