Interview Simulator · System Design
Design a URL Shortener
A full 45 minute round, one phase at a time. Each phase has a time budget, follow-up questions from the interviewer, and a checklist for your level. Reveal a phase's model answer whenever you need it; the report shows which phases you earned.
Design a URL shortener. It takes about 100 million new links and 10 billion redirects a day. Short links are 7 characters and have to resolve in under 100 ms anywhere in the world.