When promoting Kotlin over Java to your friend the first argument you’ll probably use will be its powerful syntax: in-house nullability support, default arguments, delegated properties, data & sealed classes, etc. These features are really the stuff we’re benefiting from everyday, but if we’ll take Java annotation processors then sadly the only information they can get about our code will be Java-related and no info about Kotlin-specifics. In this talk we’ll find out how to use Kotlin metadata added to the bytecode to get info about Kotlin-specific features in the code and utilise it during annotation processing.