Preceding the recent open sourcing of the standardization, the C# compilers have been open source since 2014 and are now in the dotnet/roslyn repository. After that the dotnet/csharplang split off ...

Bridge.NET is an open source C#-to-JavaScript compiler and frameworks that also allows for C# apps to be run in Web browsers. Bridge.NET has since been incorporated into the upcoming v2.0 release, ...