But wasn't open source till the end of 2015 (https://developer.apple.com/swift/blog/?id=34)
Kotlin was open sourced around 2012 and people were using it in Android apps before Google officially started supporting it in 2016.
Kotlin was open sourced around 2012 and people were using it in Android apps before Google officially started supporting it in 2016.
Swift open source 2015/12/3: https://developer.apple.com/swift/blog/?id=34