What browsers support HTML5 WebSocket API?

Client side

• Hixie-75:
  • Chrome 4.0 + 5.0
  • Safari 5.0.0
• HyBi-00/Hixie-76:
  • Chrome 6.0 - 13.0
  • Safari 5.0.2 + 5.1
  • iOS 4.2 + iOS 5
  • Firefox 4.0 - support for WebSockets disabled. To enable it see here.
  • Opera 11 - with support disabled. To enable it see here.
• HyBi-07+:
  • Chrome 14.0
  • Firefox 6.0 - prefixed: MozWebSocket
  • IE 9 - via downloadable Silverlight extension
• HyBi-10:
  • Chrome 14.0 + 15.0
  • Firefox 7.0 + 8.0 + 9.0 + 10.0 - prefixed: MozWebSocket
  • IE 10 (from Windows 8 developer preview)
• HyBi-17/RFC 6455
  • Chrome 16
  • Firefox 11
  • Opera 12.10 / Opera Mobile 12.1

Any browser with Flash can support WebSocket using the web-socket-js shim/polyfill.

See caniuse for the current status of WebSockets support in desktop and mobile browsers.

See the test reports from the WS testsuite included in Autobahn WebSockets for feature/protocol conformance tests.

Server side

It depends on which language you use.

In Java/Java EE:

• Jetty 7.0 supports it (very easy to use) V 7.5 supports RFC6455 - Jetty 9.1 supports javax.websocket / JSR 356)
• GlassFish 3.0 (very low level and sometimes complex), Glassfish 3.1 has new refactored Websocket Support which is more developer friendly V 3.1.2 supports RFC6455
• Caucho Resin 4.0.2 (not yet tried) V 4.0.25 supports RFC6455
• Tomcat 7.0.27 now supports it V 7.0.28 supports RFC6455
• Tomcat 8.x has native support for websockets RFC6455 and is JSR 356 compliant
• JSR 356 included in Java EE 7 will define the Java API for WebSocket, but is not yet stable and complete. See Arun GUPTA's article WebSocket and Java EE 7 - Getting Ready for JSR 356 (TOTD #181) and QCon presentation (from 00:37:36 to 00:46:53) for more information on progress. You can also look at Java websocket SDK.

Some other Java implementations:

• Kaazing Gateway
• jWebscoket
• Netty
• xLightWeb
• Webbit
• Atmosphere
• Grizzly
• Apache ActiveMQ V 5.6 supports RFC6455
• Apache Camel V 2.10 supports RFC6455
• JBoss HornetQ

In C#:

• XSockets.NET
• SuperWebSocket
• Nugget
• Alchemy-Websockets
• Fleck
• SignalR

In PHP:

• Ratchet
• phpwebsocket.
• Extendible Web Socket Server
• phpdaemon

In Python:

• pywebsockets
• websockify
• gevent-websocket, gevent-socketio and flask-sockets based on the former
• Autobahn
• Tornado

In C:

• libwebsockets

In Node.js:

• Socket.io : Socket.io also has serverside ports for Python, Java, Google GO, Rack
• sockjs : sockjs also has serverside ports for Python, Java, Erlang and Lua
• WebSocket-Node - Pure JavaScript Client & Server implementation of HyBi-10.

Vert.x (also known as Node.x) : A node like polyglot implementation running on a Java 7 JVM and based on Netty with :

• Support for Ruby(JRuby), Java, Grovy, Javascript(Rhino/Nashorn), Scala, ...
• True threading. (unlike Node.js)
• Understands multiple network protocols out of the box including: TCP, SSL, UDP, HTTP, HTTPS, Websockets, SockJS as fallback for WebSockets

Pusher.com is a Websocket cloud service accessible through a REST API.

DotCloud cloud platform supports Websockets, and Java (Jetty Servlet Container), NodeJS, Python, Ruby, PHP and Perl programming languages.

Openshift cloud platform supports websockets, and Java (Jboss, Spring, Tomcat & Vertx), PHP (ZendServer & CodeIgniter), Ruby (ROR), Node.js, Python (Django & Flask) plateforms.

For other language implementations, see the Wikipedia article for more information.

The RFC for Websockets : RFC6455