.NET Compiler Platform, better known by its codename "Roslyn", is a set of open-source compilers and code analysis APIs for C# and Visual Basic .NET languages from Microsoft. The project notably includes self-hosting versions of the C# and VB.NET compilers – compilers written in the languages themselves. The compilers are available via the traditional command-line programs but also as APIs available natively from within .NET code. Roslyn exposes modules for syntactic (lexical) analysis of code, semantic analysis, dynamic compilation to CIL, and code emission.