Step 1 of 13 · Intro

Design a link shortener

Billions of redirects, a few writes, and short codes that never collide.

How it works

• ›Shorten: the server stores code → long URL in a database.
• ›Open: the server looks the code up and replies with a redirect.

What you'll build

1. The API and the data behind it
2. A system that answers 500 requests a second
3. A cache, replicas and a load balancer for 50,000
4. A rate limiter that stops a scraper
5. A design that survives a cache restart, a lost server and a lost primary