Dot Net (.Net) The .NET Framework is a software framework developed by Microsoft that runs primarily on Microsoft Windows. It includes a large class library called Framework Class Library and provides language interoperability across several programming languages, saag technologies Net Framework is a software development platform developed by Microsoft for building and running Windows applications. The. Net framework consists of developer tools, programming languages, and libraries to build desktop and web applications. It is also used to build websites, web services, and games.