What is the problem here? #java #codinginterview #programming

A single server can't hold 1M WebSocket connections. With multiple servers, user A on Server 1 can't directly message user B on Server 2. Use a pub/sub system like Redis Pub/Sub — when Server 1 gets a message for user B, it publishes to a channel that Server 2 subscribes to. Horizontal scaling requires coordination. #programming #coding #developer #tech #softwareengineering