@Casey Brooks OK, but my interface returns Any as the type is not known at this point. I can't really use toInt() as this is not available on Any. Casting to Int is my only option.

I think I read the original question a bit too quickly. It looks like this is a situation of the platform Number representations not playing well with Kotlin. I’m not too familiar with Swift/obj-c, but it is documented that Swift/obj-c primitives generally don’t have enough info to the Kotlin runtime to really handle them very well https://kotlinlang.org/docs/native-objc-interop.html#nsnumber So in this case you’d probably have to cast to Long, and then use

.toInt()

on that result.

(myImplementation.get() as Long).toInt()