Kotlin
| Kotlin | |
|---|---|
 | |
| Paradigms | Multi-paradigm: object-oriented, functional, imperative, block structured, generic, reflective, concurrent |
| Family | JVM-hosted |
| Designed by | Andrey Breslav, JetBrains |
| Developer | JetBrains |
| First appeared | 22 July 2011 |
| Stable release | Kotlin 2.4.0 
/ 3 June 2026 |
| Typing discipline | Inferred, static, strong |
| Platform |
|
| OS | Cross-platform |
| License | Apache 2.0 |
| Filename extensions | .kt, .kts, .kexe, .klib |
| Website | kotlinlang |
| Influenced by | |
| Influenced | |
| V (Vlang) | |
Kotlin (/ˈkɒtlɪn/) is a cross-platform, statically typed, general-purpose high-level programming language with type inference. Kotlin is designed to interoperate fully with Java, and the Java virtual machine (JVM) version of Kotlin's standard library depends on the Java Class Library. Type inference allows for more concise syntax than Java, while null-safety features reduce a common class of runtime errors. Kotlin mainly targets the JVM, but also compiles to JavaScript (e.g., for frontend web applications using React) or native code via LLVM (e.g., for native iOS apps sharing business logic with Android apps). JetBrains bears language development costs, while the Kotlin Foundation protects the Kotlin trademark.
On 7 May 2019, Google announced Kotlin had become its preferred language for Android app developers. As of 2024, over 95% of the top 1,000 Android apps on Google Play contain Kotlin code. In May 2024, JetBrains released Kotlin 2.0 featuring the new K2 compiler—a complete rewrite offering up to twice the compilation speed of its predecessor—as well as stabilised support for Kotlin Multiplatform. That same month, Google formally endorsed Kotlin Multiplatform at Google I/O 2024, recommending it as the approach for sharing business logic across Android, iOS, and other platforms.