Follow up to ^^^ is the kotlin std lib available for native? Docs here do not mention native, maybe because it is preview. https://kotlinlang.org/api/latest/jvm/stdlib/index.html General question is what is the lowest common standard library for sharing code btw platforms? Is there/will there be a std lib with collections, file I/O, etc?

Sure, whole standard library (modulo JVM/JS-specific parts) is available. File IO is available via platform libraries available out of the box on most targets, see this example: https://github.com/JetBrains/kotlin-native/blob/master/samples/csvparser/src/main/kotlin/CsvParser.kt