SockJS!

Socket.IO aims to make real-time apps possible in every browser and mobile device, blurring the differences between the different transport mechanisms. It's care-free open source real-time 100% in JavaScript.

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.

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.

SocketCluster is an open source realtime WebSocket framework for Node.js.

Quickly and easily distribute your events between applications, services, and devices. See a log stream and debug events before they even get to your services.