The binary size is outrageous but Swift is a decent language. For many of us who want a good client (iOS) and server language, Swift is a good choice. You can w

The binary size is outrageous but Swift is a decent language. For many of us who want a good client (iOS) and server language, Swift is a good choice. You can work in a single IDE for both and even compile to WASM if that's your thing. The alternative is Kotlyn but it comes with its own set of issues. Gradle, for one, although I see that you don't need to use Groovy any more (Good!). However, it remains a rather messy language with a lot of necessary Java interop. And by confusing I mean that everyone is trying to use the language to build their own DSL. You can also use TypeScript, if Web clients are your thing. It's pretty performant and the build systems are somewhat easier to understand. Just stay away from ReactNative. The rest, Go, C#, etc, are great server-side languages but you have to use a second or third language if you want a native app and web interface.