Building a Production-Ready WebSocket Server with Node.js: Scaling to 100K Connections

Building a Production-Ready WebSocket Server with Node.js: Scaling to 100K Connections WebSocket servers promise real-time, bidirectional communication. HTTP servers promise request-response simplicity. The gap between these two paradigms is where most production incidents happen. If you have ever watched a WebSocket deployment crumble under load while your HTTP services hummed along, you know exactly what I mean. This guide walks through building a WebSocket server in Node.js that can handle 100,000 concurrent connections. Not in theory --- in practice, with code you can deploy today. Why WebSocket Servers Are Different from HTTP HTTP is stateless. A load balancer can route any request to any server, and the server does not need to remember who you are between requests. WebSocket connections are stateful. Once a client connects, it maintains a persistent TCP connection to a specific server process. That single difference changes everything about how you scale. Here is what breaks when