[gregopet]

Just use any Java framework or library, Kotlin can adapt to them quite easily.. We've used Ratpack with great success, we had to do a tiny bit of plumbing but it's great now and we open sourced our coroutine adapter (it was around 10 lines of code).

Vert.x already did the Kotlin plumbing on their own so you can use coroutines and similar goodies out of the box, Spring Boot supports Kotlin natively AFAIK, and something like Dropwizard should be easy to use as well..

Seriously, don't limit yourself, part of Kotlin's beauty is how easy it is to use it with Java products and reap immediate gains!