Introducing ASP.NET 5

In late 2014, Microsoft released all of .NET to open source under the MIT license. Visual Studio 2015 and ASP.NET 5 (previously referred to as vNext) represent the first released versions of the products since Microsoft open sourced ASP.NET and the .NET Core framework. This includes the core .NET base class libraries, the Common Language Runtime (CLR), the Just-In-Time compiler (JIT), and the Garbage Collector (GC). This new approach has resulted in many exciting changes to the product, including these:

Cross-platform support for both developing and hosting ASP.NET website on non-Windows machines

ASP.NET allowing self-hosting (also called host-anywhere) of a web application on any device (in addition to web server hosting such as IIS)

Cloud-ready, modular versions of the framework that can ship with your application as packages; can run side-by-side other versions; require only portions of the framework you intend to use (or no framework at all); and do not require machine upgrades to work

A new, unified, open-source ASP.NET compiler (Roslyn) that supports C# and Visual Basic languages and works in the background (dynamic compilation) to save you time during debug and eliminate slow startups for users following site updates

Adoption of many popular third-party client frameworks like jQuery, AngularJS, Ember, Knockout, and others

Client-side packaged management using popular web tools like Bower and Gulp

Support for responsive design with Twitter Bootstrap

Support for developing using additional code editors (like Sublime Text, Vi, and others) on different operating systems such as Mac and Linux

Cloud-ready configuration for environment variables, session, and cache

ASP.NET 5 also unifies the programming and execution models of MVC 6, Web Pages, Web API, caching, SignalR, and Entity Framework. In prior versions, many of these programming models overlapped, resulting in duplicate features that were implemented separately. This often meant unexpected behavior from similar classes. Thankfully, all these technologies are now merged, duplication has been removed, and you can write your code against a single framework.