Do you want to develop mutual TLS Web services in Kotlin? Hexagon 1.2 got released today with that feature, check the following section to learn how: https://hexagonkt.com/port_http_server/#https
You can check all project's examples and source code at GitHub : https://github.com/hexagonkt
If you give it a go, please share your feedback!
Disclaimer: I'm the project's maintainer