Design a URL Shortener
Company: Microsoft
Role: Software Engineer
Category: System Design
Difficulty: hard
Interview Round: Onsite
Design a URL-shortening service similar to TinyURL. The service should accept a long URL and return a short code, and later redirect requests for that short code to the original URL. Assume tens of millions of new URLs are created per day, and read traffic is much higher than write traffic. Discuss the API design, short-code generation strategy, storage schema, redirect path, caching, scaling, availability, expiration handling, and abuse prevention.
Quick Answer: This question evaluates a candidate's ability to design a scalable, highly available URL-shortening service, testing competencies in API design, short-code generation, storage schema, redirect flow, caching, scaling, expiration handling, and abuse prevention.