How many WebSocket connections have you managed to maintain on a single server?

The number of WebSocket connections that can be held on a single server depends on many factors:

• Hardware resources of the server (CPU, RAM, network).
• Operating system and its settings (e.g., limits on the number of open files).
• Efficiency of the server implementation and the library used.
• Load on each connection (message frequency, data size).

In practice, with optimal configuration and the use of non-blocking I/O, one server can support tens or hundreds of thousands of simultaneous WebSocket connections.

For example, in large systems written in Go using efficient libraries (such as gorilla/websocket) and proper OS configuration (increasing open file limits, network parameter tuning), it is possible to reach around 100,000+ connections on a single server.

To achieve such performance, it is important to:

• Use asynchronous processing and minimize blocking.
• Configure the OS (ulimit, sysctl) to support a large number of open files and sockets.
• Optimize message processing and minimize CPU load.

In real projects, clustering and load balancing are often used to distribute connections across multiple servers.