WebSockets
1 open source tools compared. Sorted by stars — scroll down for our analysis.
| Tool | Stars | Velocity | Language | License | Score |
|---|---|---|---|---|---|
| 7.0k | +1/wk | Java | Apache-2.0 | 77 |
Our Analysis
If you need real-time communication in a Java backend — chat, live updates, push notifications — and you want Socket.IO compatibility, netty-socketio is a Java implementation of the Socket.IO server protocol built on Netty's high-performance networking. This lets your Java server speak Socket.IO to any Socket.IO client (JavaScript, Swift, Kotlin, etc.). You get namespaces, rooms, event-based messaging, and automatic transport fallback (WebSocket to long-polling). Netty underneath means it handles thousands of concurrent connections without breaking a sweat. Fully free. Apache 2.0 license. No paid tier. Java teams building real-time features who don't want to run a separate Node.js service just for Socket.IO will find this useful. It's been around since 2012 and has 7k stars, so it's proven. The catch: development has slowed significantly (velocity of 1 star/week). It doesn't support the latest Socket.IO v4 protocol features. If you're starting fresh, consider whether you actually need Socket.IO compatibility or if plain WebSockets (with Spring WebSocket or Quarkus) would be simpler.