Kotlin Multiplatform (KMP) is a technology by JetBrains that lets you write shared Kotlin code that compiles to multiple platform targets: Android (JVM), iOS (Native), Desktop (JVM), Web (WASM/JS), server-side (JVM), and more. Unlike full cross-platform frameworks, KMP does not force you into a single UI toolkit or runtime; you decide how much code to share and keep native platform APIs where they matter most. KMP was declared Stable in November 2023. In May 2025, Compose Multiplatform 1.8.0 declared iOS support Stable, meaning the full stack (shared logic AND shared UI) is now production-ready for Android and iOS.