Design Meta Post Privacy
Hard · System Design · about 45 minutes
Asked at Meta, LinkedIn, Snap, Pinterest.
Design the system that enforces post visibility on a social network with billions of users. Authors choose Public, Friends, Friends of friends, Only me, or a custom list, and blocks always apply. Feeds, profiles, direct links, search and notifications must never show a post to someone who isn't allowed to see it, and unfriending or blocking must take effect within seconds.