The design library
Building blocks, complete architectures, and variations worth comparing. Search by the problem you want to solve or a component you want to understand.
Classic designOfficial
Design a team chat app like Slack: channels and DMs in real time, threads, unread counts and search. One-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Push, email, SMS and in-app for a billion deliveries a day: priorities that never wait, promotions that never arrive late, no duplicates a user would notice. One-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Live comments for millions of viewers: SSE streams, a Redis channel per video with co-located viewers, sampling and CDN snapshots for hot videos: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
Photos and videos for 500 million daily users: presigned multipart uploads, a processing pipeline, CloudFront and a hybrid fan-out feed: one-hour boards for junior, senior and staff, with the theory behind them.
Classic designOfficial
A home feed for 2 billion users: fan-out on read, on write, and the hybrid for huge accounts, with precomputed feeds, cursors and hot posts: one-hour boards for junior, senior and staff, with the theory behind them.
Building blockOfficial
Push new items into followers' timelines at write time, except for accounts with huge followings, whose posts are pulled and merged at read time.