Design Instagram
Medium · System Design · about 45 minutes
Asked at Meta, Pinterest, Snap, ByteDance, Google, Duolingo, Match Group.
Design a photo-sharing service like Instagram. Users upload photos, follow each other and scroll a feed of recent photos from the people they follow. Assume ~500M daily users, ~100M photo uploads per day and a read-heavy workload (~100 reads per write); a new photo may take a few seconds to appear in followers' feeds.