WebSocket is a technology providing for bi-directional, full-duplex communications channels, over a single Transmission Control Protocol (TCP) socket. The technology is designed to be implemented in both web browsers and web servers but it can also be used by any client or server application.

WebSocket4Net is a .NET websocket client implementation tool. It had its origins in SuperWebSocket WebSocket Client. However, for a better development of the websocket client, the tools was separated from SuperWebSocket and was renamed WebSocket4Net.

WebSocket4Net is compatible with many websocket drafts including Hybi-00, Hybi-10 and RFC6455. It also provides websocket client implementation for numerous different kinds of runtime including .Net 2.0, .Net 3.5, .Net 4.0, Mono, Silverlight, WindowsPhone, Xamarin.Android and Xamarin.iOS.