A working study log for Staff-level system design interviews. Each entry documents the full design process — requirements through deep dives — with diagrams, tradeoffs, and honest reasoning throughout.
A URL shortening service handling 100M creates/day and 1B redirects/day. Covers short code generation, cache strategy, redirect semantics, and abuse prevention.
In ProgressEvery design follows the 6-step framework. Each page starts simple — a base case that works — then adds complexity in layers. Diagrams are always inline. Tradeoffs are named explicitly, not buried. The goal is a page you can study from, not just skim.