Some time ago I promised a Proof Of Concept implementation of widgets for kotlin jupyter kernel. Today I finally had some time to work with it. Here it is: https://github.com/altavir/jupyter-mpp-demo. No documentation yet, but there is a demonstration notebook included. Currently only checkbox and text field are implemented and there are some rough edges ( for example only one instance of the same widget is connected), but it seem to be alright for POC. The architecture is extensible, so it is possible to add new widgets quite easily. If someone wants, it could be improved to the full-scale widgets library. Also you can use this example as a template for your own full-stack plugins. As always, thanks to @Ilya Muradyan for fantastic cooperation.

Small demo. Looks great :)