Comment by mwcampbell
17 hours ago
This is probably biased by the specific multi-platform apps I've worked on, but my default assumption is that sooner or later, any non-trivial multi-platform app will need to reach for something that doesn't already have a KMP library and that, on Android, might require compiling native code via the NDK. Rust has a way bigger library ecosystem than KMP. So I figure one might as well do the cross-platform core in Rust and add that FFI boundary early, but managed by something like uniffi-rs. And, I've seen it work in a few real projects now, with just a little build system friction up front. So in what sense is Rust uncompetitive for this use case?
KMP can call into native libraries easily. C FFI is not a competitive advantage.
Rust has a smaller library ecosystem, I'd say. Kotlin can use Java libraries on the server side, and on the client side on Android, and the ones needed on iOS are easy to convert to KMP - IntelliJ can do it semi-automatically. And KMP has the libraries that matter on mobile, for hardware access, animations and so on.