Socket.io!

What is reep.io?reep.io uses modern WebRTC technology to enable peer-to-peer file transfers between two browser.

JBoss is Red Hats Java EE 5-compliant (soon Java EE 6-compliant) application server. It is, as with Red Hat itself, dual-licensed either as open source (community edition) or commercially (enterprise edition).

A WebSocket Implementation for Node.JS ( Draft -08 through the final RFC 6455 )

Bone.io allows you to build realtime JavaScript apps using WebSockets to deliver "hot" data to the browser. This enables you to easily construct rich, highly responsive user interfaces.

The Jetty Web Server provides a HTTP server and Servlet container capable of serving static and dynamic contend either from a standalone or embedded instantiations.

Simperium is a service for developers to move data everywhere it's needed, instantly and automatically.

Lightstreamer is a server for delivering real-time messages to browser-based and mobile applications, using WebSockets and HTTP. Features include dynamic throttling, bandwidth and frequency control, delta delivery, and total control over security and the quality of service.

Faye is a set of tools for simple publish-subscribe messaging between web clients. It ships with easy-to-use message routing servers for Node.js and Rack applications, and clients that can be used on the server and in the browser.

Primus, the creator god of transformers but now also known as universal wrapper for real-time frameworks. There are a lot of real-time frameworks available for Node.js and they all have different opinions on how real-time should be done. Primus provides a common low level interface to communicate in real-time using various real-time frameworks.

Eventlet is a concurrent networking library for Python that allows you to change how you run your code, not how you write it.

gevent is a coroutine -based Python networking library that uses greenlet to provide a high-level synchronous API on top of the libev event loop.

greenlet - Lightweight in-process concurrent programming

JsSIP, the JavaScript SIP library