Design News Feed

Design a news feed system: users follow other users and see a reverse-chronological (or ranked) feed of posts from the people they follow, with support for posting, likes, and real-time-ish delivery at very large scale. Problem Statement Design a news feed system: users follow other users and see a reverse-chronological (or ranked) feed of posts from the people they follow, with support for posting, likes, and real-time-ish delivery at very large scale. This was an Apple phone screen for a Machine Learning Engineer, framed as an ML system design round. The interviewer expected you to cover the core feed architecture (fan-out on write vs. read, the celebrity problem, timeline caches) before layering on ranking concerns.