Design a URL Shortener
A worked system design interview answer for a URL shortener: short code generation, a 302 redirect, and why the cache matters more than the algorithm.
Design a Rate Limiter
A worked system design answer for building a rate limiter service: where counters live, avoiding a race under concurrency, and fixed vs sliding windows.
Design Pastebin
A worked system design answer for Pastebin: separating metadata from large content, and using content-hash deduplication so identical pastes store once.
Design a Key-Value Store
A worked system design answer for a distributed key-value store: consistent hashing, quorum reads/writes, and resolving conflicting concurrent writes.
Design a Parking Lot System
A worked system design answer for a parking lot system, where the real challenge is correctness under concurrency, not scale — never double-book a spot.