This project is read-only.

NEWS: Roslyn has moved to GitHub

The move has completed and our new address is

Move announcement

The Roslyn Project has been moved under GitHub, joining the rest of the .NET team over there.

  • This is be a simple switch – turn off CodePlex, turn on GitHub. You’ll be able to see our checkins there, for example.
  • We're open for pull requests there.
  • We’ll be using GitHub Issues for both discussions and bugs after the switch.
  • We will try to move over outstanding bugs from CodePlex, but this is the trickier part of the plan. Stay tuned.
  • We will also do our best to preserve check-in history.
  • We will be under the .NET Foundation over there, as the “Compilers” project.
We will update this page with the forwarding information when the switch is complete mid-week. I’ll also be blogging about some of the additional OSS work we’re about to embark on in a week or two.

--Matt Gertz--*
Group Software Engineering Manager, “Roslyn”

Welcome to the .NET Compiler Platform ("Roslyn")

The .NET Compiler Platform ("Roslyn") provides open-source C# and Visual Basic compilers with rich code analysis APIs. You can build code analysis tools with the same APIs that Microsoft is using to implement Visual Studio!

Try new language and IDE features

Just want to provide feedback on new language features and IDE features?
  • Try out Visual Studio 2015 Preview, which has our latest features built-in.
  • You can also try April's End User Preview, which installs on top of Visual Studio 2013.
    • (note: this VS 2013 preview is quite out of date, and is no longer updated)

Build tools that understand C# and Visual Basic

Get started building diagnostics, code fixes, refactorings and other code-aware tools!

  1. Set up a box with Visual Studio 2015 Preview. Either...
  2. Install the Visual Studio 2015 Preview SDK. You'll need to do this even if you're using the Azure VM image.
  3. Install the SDK Templates VSIX package to get the Visual Studio project templates.
  4. Install the Syntax Visualizer VSIX package to get a Syntax Visualizer tool window to help explore the syntax trees you'll be analyzing.
Or, you can grab the latest NuGet Roslyn compiler package. From the NuGet package manager console:

Install-Package Microsoft.CodeAnalysis -Pre

Source code

  • Clone the sources:
git clone

Get started


Some of the best ways to contribute are to try things out, file bugs, and join in design conversations. Looking for something to work on? The list of up-for-grabs issues is a great place to start.

Last edited Feb 14, 2015 at 11:22 PM by nmgafter, version 45