Roslyn, a .NET compiler platform under the Apache License 2.0, is a next-generation set of compilers for C# and VB.NET written entirely as managed code. It provides access to the compiler as a service and includes code analysis APIs allowing developers to access information from the compiler that was previously treated as a black box, for example syntactic and semantic models. The most immediate impact should be seen in enhancements to .NET IDEs through refactoring and code generation tools. We also expect to see improved code diagnostics and static analysis, although it will be interesting to see what the community comes up with. Meanwhile Xamarin has a Mono-compatible copy of Roslyn source code hosted on GitHub and plans to bundle Roslyn’s compilers with Mono as it stabilizes, in addition to integrating the best parts into their code base.