It's well entrenched in server development. The notion that it is Android only is a myth. There are an enormous amount of Kotlin server developers out there. Sp

It's well entrenched in server development. The notion that it is Android only is a myth. There are an enormous amount of Kotlin server developers out there. Speaking as someone who has done Java for 25 years and Spring/Spring boot for the last twelve years. The last five of which have been exclusively in Kotlin. I know this market. The Kotlin ecosystem outside of Android is huge. Every Java server framework that still matters supports Kotlin: Spring, Quarkus, Javlin, Vert.x, etc. It's for a simple reason: Kotlin worked nicely with those frameworks before they even actively started supporting it and people used it for the same reason Android developers started using Kotlin. It's just way nicer to use than Java and there are no downsides to using Kotlin with a framework that is exclusively designed for Java. It just works. So several years ago, all those frameworks started adding Kotlin extension functions to their libraries and designing features specifically for Kotlin users. Android developers got a little headstart on the transition to Kotlin for two reasons: 1) google had some issues with Oracle that caused the Android version of Java to be stuck on a version without lambda functions for quite some time 2) Android developers frequently end up doing greenfield projects and they'll grab whatever works when that happens. So, about seven years ago, Kotlin was a drop in replacement for Java on Android that had a lot of nice language features that Java simply did not have. Irresistable for Android developers stuck on the Java 5/6 feature set. Google upgraded the java language version used on the platform over time. But most of that happened after they endorsed Kotlin as the main language. Something similar happened with Spring but just a lot slower. I used Kotlin with Spring 4.x already in 2018. It had absolutely zero kotlin support but it was a nice upgrade nonetheless. Just worked and added a lot of value (data classes, nullability, etc.). With Version 5.x they added a lot of Kotlin support and they've been iterating on that for the last four years.