ASP.NET MVC 5 is a framework for building scalable and standards-based web applications using established design patterns and the power of ASP.NET and .NET. It allows applications to run on IIS or self-host on Windows, Linux, and Mac OS X using the .NET runtime and libraries delivered via NuGet. Applications are built with MSBuild/Roslyn and hosted by Kestrel, IIS, or HTTP.SYS, with libraries from NuGet rather than the GAC.