Introduction
SignalR is a new library for ASP.Net Development companies that is used to add real time web functionality to ASP.NET applications . Real Time functionality is the ability to have put your server side code content to connected clients instantly as it becomes available, rather than having the server wait for a client to request a new data.
SignalR provides a bidirectional communication channel between (web) clients and a server side (web) application. SignalR is not limited to web application. A client can be every application or web page which uses JavaScript or .NET Framework 4.5 (or 4 with some restrictions) - like Windows Phone apps, SilverLight or Console applications. A SignalR server application has to be build with .NET Framework 4.5 (or 4 with some restrictions).

SignalR provides two communication levels:
- Persistent Connection API - low level, message-oriented communication
- Hub API - high level, allows direct call of client and server methods
The Hub API offers the most convenient and preferred communication API. The Persistent Connection API might only be interesting, if you need to integrate with an existing message based server application or if you need for some reason detailed control on the message level.