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.NET is open-source

Open-source on GitHub

.NET Core is an open-source and cross-platform version of .NET that is maintained by Microsoft and the .NET community on GitHub.

All aspects of .NET Core are open-source including class libraries, runtime, compilers, languages, ASP.NET Core web framework, Windows desktop frameworks, and Entity Framework Core data access library.

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100,000+ OSS contributions 3,700+ OSS company contributors

Open for contributions

Yes, we do accept contributions! As with any open-source project we don't just blindly accept everything. The pull requests we receive are reviewed for quality and to ensure they align with the goals of .NET.

We've already accepted over 100,000 contributions from developers from over 3,700 companies.

Learn more about contributing to .NET

MIT and Apache 2 licenses

The various parts of .NET Core are maintained in different GitHub repositories. These repositories typically use the MIT or Apache 2 licenses. Some repositories license documentation and other forms of content under Creative Commons Attribution 4.0.

See specific repositories to understand the license used.

.NET Foundation

The .NET Foundation is an independent organization to foster open development and collaboration around the .NET ecosystem.

Over 50 open-source projects are part of the .NET Foundation. Microsoft as well as others like Pivotal, Google, Samsung and Red Hat have made significant contributions, in addition to our broader community. See how you can get involved with the .NET Foundation.

Visit the .NET Foundation website

More than just code

In addition to the code we aim to make every aspect of .NET as open as possible. The documentation is open-source. On the .NET team at Microsoft we open up our day to day work with initiatives like our open API review process and the community standups.

The Open-source library guidance provides recommendations for .NET developers to create high-quality .NET libraries. The guidance itself is open-source on GitHub and developed in partnership with popular library authors.


You can build your own version of .NET from source code, but most production apps need a supported version of the platform.

Microsoft ships official releases that are built and tested on Microsoft-maintained servers in Azure and supported just like any Microsoft product. See the .NET support policy for details.

Red Hat supports .NET Core on Red Hat Enterprise Linux (RHEL). Red Hat builds .NET Core from source and makes it available in the Red Hat Software Collections. Red Hat and Microsoft collaborate to ensure that everything works well on RHEL.

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