Scaling WebSockets: Handling Millions of Connections

Issue #92: System Design Interview Roadmap • Section 4: Scalability • July 7, 2025

📋 What We'll Master Today

• Connection Capacity Engineering - Breaking the 10K connection ceiling per server

• Intelligent Load Balancing - Sticky sessions with consistent hashing at scale

• Cross-Server Broadcasting - Redis pub/sub for distributed message delivery

• Production Hardening - Memory leak prevention and ghost connection cleanup

• Complete Implementation - Build a Discord-scale WebSocket system from scratch