I've built and shipped some native-UI cross-platform apps to millions of devices, powered by a Go shared library. It works. It's fantastic to use the same language on client and server, and the end-to-end testing story is really strong.

However, in my opinion, "Go Mobile" is a bit of a red herring if you just want a cross-platform shared library. I wouldn't recommend starting there.

It's optimised for writing and packaging an entire app in Go. Incremental builds don't work well (or at all), and cobbled-together "build system" is more to debug. It's also oriented around iOS and Android, which isn't great if you eventually want a native desktop app too. The generated bindings are okay, but the author's approach of using Protobuf (or some kind of wire format + simple API) means you don't really need them.

I found that it's more straightforward to just compile Go code into a library that can be called from C -- and thus can be called from anywhere. Call into it natively from Swift, and via JNI on Android and desktop JVM. With the right toolchain, you can cross-compile pretty easily too.

The biggest issue is that on Android you often want to talk to the OS, but the OS only speaks JVM. https://github.com/timob/jnigi "solves" this, although you will hate your life manually constructing JVM calls that you can't easily test.