HardSocial45-55 min

Design a Social Network

Design an Instagram/Facebook-like social platform with feeds, posts, followers, and real-time interactions.

MetaInstagramTwitterLinkedIn

Functional Requirements

User profiles with follow/unfollow
Post creation (text, images, videos)
News feed generation
Like, comment, and share functionality
Notifications for interactions
Direct messaging (basic)

Steps (0/6)

Step 1: Requirements & Scale

Clarify: 500M DAU, 200M posts/day, average user follows 200 accounts. Feed: 80% of user time. Read-heavy: 10:1 ratio. 95th percentile: feed loads in <500ms.

Key Points

500M DAU, 200M new posts/day = 2,300 posts/sec
Feed reads: 5B/day = 60K feed loads/sec
Average user follows 200 accounts
Celebrity problem: some accounts have 100M+ followers

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