NEWS: Because the DLR is in the C#/Roslyn team (since before C# 4.0), parts of the DLR have moved to github and are now fully open source as part of the .NET Core project and Roslyn.

Eventually, all the sources that shipped with the DLR in Visual Studio and .NET may move to github, but the github project does not include all of .NET yet.

The sources for DLR pieces that shipped only on codeplex and never with Visual Studio / .NET remain here and are actively developed at and IronPython.

Please communicate, open bugs, contribute code, etc., at Microsoft/dotnet for the parts that shipped in Visual Studio and .NET. If you're not sure, start on the github site.

The Dynamic Language Runtime enables language developers to more easily create dynamic languages for the .NET platform. In addition to being a pluggable back-end for dynamic language compilers, the DLR provides language interop for dynamic operations on objects. The DLR has common hosting APIs for using dynamic languages as libraries or for scripting in your .NET applications. This project provides one stop shopping for the DLR components, our open source implementations of IronPython and IronRuby, documentation, and samples.

Contact Information

Please send an email to if you have any questions, comments, or feedback.

Last edited May 4 at 7:26 PM by billchi, version 38