Design an Instagram-like Feed System
Company: OpenAI
Role: Software Engineer
Category: System Design
Difficulty: medium
Interview Round: Technical Screen
Design an Instagram-like photo-sharing application.
Your design should support:
- Users creating posts containing photos or short videos.
- Users following other users.
- A home feed that shows recent and relevant posts from followed accounts.
- High read traffic for feeds and high write fan-out for popular accounts.
Focus especially on feed generation and delivery. Cover:
1. Core components and APIs.
2. Data flow from post creation to storage to feed generation to feed delivery.
3. Storage choices for posts, media, follow graph, and feeds.
4. Push, pull, and hybrid feed generation strategies.
5. How to handle celebrities or creators with millions of followers.
6. How to scale database reads and avoid feed-read bottlenecks.
Quick Answer: This question evaluates a candidate's competency in large-scale distributed system design, focusing on feed generation, data modeling, storage choices, scalability, and trade-offs related to high read traffic and write fan-out.