Kotlin

Kotlin is a statically typed programming language developed by JetBrains, first announced in 2011 and reaching version 1.0 in February 2016. It compiles to JVM bytecode, JavaScript, and native binaries via LLVM. Google designated Kotlin the preferred language for Android development in 2019, and the Android SDK now treats it as the primary language for new APIs.

The current release is Kotlin 2.3, which shipped in December 2025. The language emphasizes null safety at the type-system level, concise syntax (data classes, extension functions, coroutines), and full interoperability with existing Java code. Kotlin Multiplatform reached production status, allowing teams to share business logic across Android, iOS, web, and server targets from a single codebase.

The official documentation covers the language from getting started to advanced topics. The compiler and standard library are open source on GitHub under the Apache 2.0 license.