Does anybody know how hard it is to configure a notebook to run both Python and Kotlin? Been having a good time writing Kotlin notebooks for a customer but occasionally I want to show Python sidebars too.

Do you need to share the state between Kotlin and Python parts?

Currently, no : )

If no, it's possible to achieve it with Jython library (https://www.jython.org/) and Kotlin kernel code preprocessing (see https://github.com/Kotlin/kotlin-jupyter/issues/223#issuecomment-839812237). I'd say it's rather easy)

Okay thank you I'll look into this...

I'd love to see this type of language-interop as well. I'm more interested in R though, which is still my preferred choice for statistical visualzation. In particular since kotlin needs to catch up with more established data science language, good interop would certainly help to build a bridge.

Beakerx allows to mix python, R and kotlin cells, but is has quite outdated kotlin kernel. It is possible to create a super-kernel, that allows different languages, but in general, common state is very hard to implement.