It's a programming language that looks very similar to Ruby in syntax (if you are familiar with Ruby), but it's compiled, so by switching from Ruby to Crystal for this tool I was able to provide standalone executables which are easier to use. With the Ruby version instead my users had to set up Ruby or Docker, which was not optimal.
Regarsing the standalone executable, do I only have to compile it once to be able to run on Win, Linux & Mac? Or do I have to compile it on each OS?
You need to compile a different binary for each OS as they are not compatible :)