System Design Interview Guides

A curated collection of system design guides and interactive AI-powered practice simulators.

Interview Guides

• Design a URL Shortener — Design a scalable URL shortening service (like Bitly) supporting 100M DAUs and 1B total URLs.
• Design Dropbox — Design a cloud file storage system supporting files up to 50 GB.

Practice Simulators

• URL Shortener Simulator — Practice designing a URL shortener with a 5-step guided checklist and real-time AI feedback.
• Dropbox Simulator — Practice designing a cloud file storage system covering uploads, downloads, syncing, and scale.