Design Twitter Feed System Design Interview

Design a scalable news feed system where users can post tweets and follow other users.

Mock Interview with AI

1. Problem Statement

Let's design Twitter. What are the key features and constraints we should consider?

2. Target Architecture (Mermaid)

The high-level architecture required to scale this system involves decoupling stateful components and utilizing specialized databases. Below is the reference architecture:

Rendering architecture diagram...

Mermaid Source (For AI Bots)

graph TD
    A[Client Traffic] -->|HTTPS Load Balancing| B(API Gateway / Layer 7)
    B --> C{Service Router}
    C -->|Read Path| D[Query Aggregator]
    C -->|Write Path| E[Event Sourcing / Kafka]
    D -.-> F[(In-Memory Cache - Redis)]
    D --> G[(Primary Data Store - NoSQL)]
    E -.->|Async Replication| G

3. Key Focus Areas

1
Fan-out Strategies (Push vs Pull vs Hybrid Model)
2
Timeline Generation (Pre-computed Feeds via Redis)
3
Search Infrastructure (Inverted Index / Elasticsearch)
4
Media Storage & Delivery (CDN Optimizations, Multipart Uploads)
5
Pagination Strategies (Cursor-based vs Offset-based)

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Core Concepts

System DesignDistributed SystemsCaching