I the company I've been working at in Austin and we've been increasingly choosing Kotlin for our backend services as well. We started with Scala and found the ramp up to be tough. I came from a company that used mostly Ruby before and had no JVM experience at all and I found kotlin really easy to get productive with in a short amount of time. I actually prefer it in many ways not to everything else I had done before (I think I just really like static typing).