[meibo]

Sadly(or luckily, for the people that haven't had any contact with the ecosystem), you must have missed the semi-recent open source developments around .NET Core. It's open, has a very healthy community and is well supported by Microsoft.

Sure, back in the days when you had to rely on Mono for cross-compact, this is exactly the answer you'd expect from anyone, but it couldn't be further away from the truth nowadays with the modern runtime and ASP .NET Core.