The .NET Compiler Platform ("Roslyn") provides open-source C# and Visual Basic compilers with rich code analysis APIs. It enables building code analysis tools with the same APIs that are used by Visual Studio.

Just want to provide feedback on new language features and IDE features?

• Try out Visual Studio 2015 Preview, which has the latest features built-in.

  Want to keep your box clean? You can use prebuilt Azure VM images with VS 2015 Preview already installed.

• You can also try April's End User Preview, which installs on top of Visual Studio 2013. (Note: The VS 2013 preview is quite out of date, and is no longer being updated.)

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

To get started on Visual Studio 2015 Preview:

1. Set up a box with Visual Studio 2015 Preview. Either install Visual Studio 2015 Preview, or grab a prebuilt Azure VM image.
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.

To get started on Visual Studio 2015 CTP 5:

1. Set up a box with Visual Studio 2015 CTP 5. Either install Visual Studio 2015 CTP 5, or grab a prebuilt Azure VM image.
2. Install the Visual Studio 2015 CTP 5 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

• Clone the sources: git clone https://github.com/dotnet/roslyn.git
• Enhanced source view, powered by Roslyn
• Building, testing and debugging the sources

• Roslyn Overview
• Samples and Walkthroughs
• Syntax Visualizer Tool
• Roadmap
• Language Feature Status
• Language Design Notes
• FAQ

Some of the best ways to contribute are to try things out, file bugs, and join in design conversations.

• How to Contribute
• Pull requests: Open/Closed

Looking for something to work on? The list of up for grabs issues is a great place to start.

This project is part of the .NET Foundation along with other projects like the class libraries for .NET Core.