Social News Feed – Starter Architecture

Context: Early-stage social app. 10k users, ~100 posts/day. Single region.

Starter Design

• Database: Single PostgreSQL instance. Tables: users, posts, follows.
• API: REST. GET /feed returns posts from followed users, ordered by time.
• Logic: Fan-out on read. Query: join follows + posts, sort, limit.

Why This Works for Starter

• Simple, no caching needed
• Easy to reason about and debug
• Adequate latency at this scale

Inline Check 1

At what scale would you consider adding a cache layer?

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