.NET Framework .NET Framework .NET Framework component stack Developer(s) Microsoft Initial release 13 February 2002 ; 13 years ago Stable release 4.6 (4.6.00081.00) / 20 July 2015 ; 3 months ago Operating system Windows 98 or later, Windows NT 4.0 or later Type Software framework License Mixed; see § Licensing Website microsoft .com /net .NET Framework (pronounced dot net ) is a software framework developed by Microsoft that runs primarily on Microsoft Windows . It includes a large class library known as Framework Class Library (FCL) and provides language interoperability (each language can use code written in other languages) across several programming languages . Programs written for .NET Framework execute in a software environment (as contrasted to hardware environment), known as Common Language Runtime (CLR), an application virtual machine that provides services such as security, memory management , and exception handling .