Microsoft’s .NET programming framework is about to become open source, the company announced. Not only that, but a big chunk of the .NET core will soon be made compatible for machines running either the Linux or Mac operating systems. Microsoft has also promised that the software Relevant Products/Services development platform will be entirely language agnostic.

The announcement was made through a blog post on the .NET Foundation’s Web site and a post on the blog of corporate vice president of Microsoft’s Developer Division S. Somasegar, both published on Wednesday, and at its Connect() virtual developer event taking place this week.

Cross-Platform Functionality

The .NET framework serves as the foundation that powers many components of the Windows operating system and other Microsoft programs.

Microsoft launched the .NET Foundation in April to serve as an independent forum to encourage the development of open source technologies for the .NET toolset. Some of the code for the framework had already been made publicly available through the .NET Foundation, including key components such as ASP.NET and the C# compiler.

But Wednesday’s announcement includes the full .NET server-side core stack, including the Common Language Runtime and .NET Base Class libraries. The company has already set up a GitHub repository to allow developers to access the code.

The company did not indicate what date the .NET framework would be made open source, other than to say that the stack would be made available “over the coming months.” The projects will be released under the MIT open source license and Microsoft said it would release explicit statements clarifying the patent rights to .NET.

The announcement should help make things easier for developers looking to write Web applications that can run on any server, without having to rely on technologies such as Oracle’s Java for cross-platform functionality. The move represents a significant shift for Microsoft which has historically avoided opening up its proprietary source code to other developers.

Enterprise-Ready

According to Somasegar’s blog post, there are more than 1.8 billion installations of .NET. Opening the framework up to Apple’s OS X and the open source Linux operating system could dramatically increase that number. “This will provide great new opportunities and flexibility for .NET developers, and enable .NET to be used in many new application scenarios,” Somasegar said in his blog post.

Developers had previously been able to implement some .NET technologies for non-Windows platforms through the Mono Project, a partnership between Microsoft and development toolmaker Xamarin, which built open source implementations of the framework for enterprises. But now future implementations will be spearheaded by Microsoft.

“We are excited to be working closely with the Mono community on this effort, to jointly deliver an open source, enterprise Relevant Products/Services-ready .NET implementation for the server to Windows, Linux and OS X,” Somasegar said.

The next edition of .NET, dubbed .NET 2015, includes improvements to the Windows Presentation Foundation, and ASP.NET 5, which has been re-engineered to focus more heavily on cloud Relevant Products/Services-based applications.