Step 1 of 13 · Intro

Design a ranked feed

Votes pouring in, and a ranking that stays fresh and fair.

How it works

• ›Read: show a precomputed ranking.
• ›Vote: record the vote, recompute scores in the background.

What you'll build

1. The API and data for posts and votes
2. A system that answers 800 requests a second
3. A cached front page within a budget
4. A queue and workers that tally votes
5. A design for a viral post and a rate limiter against vote bots
6. A system that survives a cold cache, a lost server and a lost primary