Back-of-the-envelope math for a URL shortener — QPS, storage growth over five years, bandwidth, and cache sizing using the 80/20 rule. The exact numbers interviewers expect you to produce on a whiteboard.
The schema, REST API contracts, rate limiting strategy, and SQL-vs-NoSQL decision for a URL shortener — the implementation details interviewers probe once the high-level architecture is settled.
Everyone can design a URL shortener that works for 10 requests a second. Here's what actually breaks when you hit 10,000 requests a second: database hotspots, cache stampedes, hash collisions, and the geographic latency problem nobody mentions in the whiteboard round.
A complete walkthrough of the URL shortener interview question — requirements gathering, architecture, hash generation strategies, and read-heavy scaling patterns interviewers actually look for.
How to Ace the SWE Phone Screen in 2026. Updated June 2026 with verified data.
How Amazon Evaluates SWEs in Interviews. Updated June 2026 with verified data.