Design an Instagram-style news feed
Company: Meta
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Onsite
Design a news feed system similar to Instagram.
Requirements:
- Users can follow/unfollow others.
- Users create posts (photo/video metadata; media storage is separate).
- Home feed shows a ranked/paginated list of posts from followed accounts (plus optional recommendations).
- Support high read traffic, infinite scroll, and freshness (new posts appear quickly).
- Handle privacy (private accounts) at least at a basic level.
Out of scope (optional): full recommendation ML, stories, ads.
Quick Answer: This question evaluates a candidate's ability to design scalable, low-latency social feed systems, testing competencies in distributed systems, data modeling, caching, ranking and pagination, consistency and freshness, and basic privacy/access control.