Congrats Guillaume! How much of ScalaKata code is in there? Sorry if I missed it in the post, but is Scastie open source? I'd love to finally fix scalatutorials.com :)
p.s. did you guys consider using a "serverless" architecture to isolate runners instead of docker? Also, are you running it with java -Djava.security.manager? If not then why?
The security manager can be disabled using reflection. If you don't allow you loose some libraries like Akka. The main thing that is missing from ScalaKata is autocompletion and it will be implemented in the summer during the GSOC. AWS lambda could be worth investigating. We don't expose an API for evaluating but others have expressed this need. Can you create an issue on GitHub for that?