A hand-picked guide to Kotlin.
The JetBrains ecosystem, the open-source repositories, the companies shipping it in production, recommended books, peer-reviewed research, and the people behind the language.
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Kotlin MultiplatformShare code across Android, iOS, web, desktop, and the server.
Compose MultiplatformJetBrains' declarative UI framework for every Kotlin target.
KtorAn asynchronous framework for connected clients and servers.
ExposedA Kotlin SQL framework and lightweight ORM from JetBrains.
Kotlin NotebookInteractive notebooks for data exploration and prototyping.
Compose Hot ReloadInstant UI iteration while you build Compose apps.
JetBrainskotlinThe Kotlin programming language and its compiler — the anchor of the whole ecosystem.
Kotlinkotlinx.coroutinesThe official coroutines library — structured concurrency, channels, and Flow.
Kotlinkotlinx.serializationOfficial multiplatform serialization with a compiler plugin and pluggable formats.
JetBrainscompose-multiplatformJetBrains' modern declarative UI framework for Android, iOS, desktop, and web.
ktorioktorAn asynchronous Kotlin framework for building connected clients and servers.
squareokhttpThe de facto HTTP client for the JVM, Android, and GraalVM.
squareokioA modern I/O library that complements java.io across Android, Java, and KMP.
squareleakcanaryThe memory-leak detection library that became standard on Android.
cashappsqldelightGenerates typesafe Kotlin APIs from your SQL statements.
afollestadmaterial-dialogsA clean, modern dialogs API for Kotlin and Android.
androidnowinandroidGoogle's fully-functional Android sample built entirely with Kotlin and Compose.
googleioschedThe official Google I/O Android app — a long-running reference codebase.
JunkFood02SealA polished Android video and audio downloader built with Compose.
mihonappmihonA free and open-source manga reader for Android.
open-anianimekoA 100% Kotlin and Compose Multiplatform anime streaming app.
amir1376ab-download-managerA cross-platform desktop download manager written in Kotlin.
The language-learning app shares core logic across platforms with Kotlin Multiplatform.
Uses Kotlin Multiplatform to share logic for its internal mobile studio apps.
Expanded Kotlin Multiplatform from payments into wider areas of its consumer app.
Shares over 80% of its logic across mobile platforms with Kotlin.
Reports millions of lines of Kotlin across its internal and external Android efforts.
Uses Kotlin to power the future of its Jira Software cloud products.
Built the foundational core of its Experience Platform with Kotlin.
Quantum Ledger Database ships a public server-side Kotlin case study.
Bitkey, its Bitcoin wallet, runs a 95% shared mobile codebase via KMP.
The award-winning task manager from Doist is built on Kotlin Multiplatform.
Adopted Kotlin Multiplatform after evaluating other cross-platform options.
Combined a Kotlin migration with Kotlin Multiplatform across its ride-hailing app.
Uses Kotlin Multiplatform to share common application logic across clients.
Runs Kotlin-backed banking systems and mobile experiences.
Shares its chat engine logic across mobility apps through Kotlin Multiplatform.
Incrementally shares logic across iOS, Android, and web with Kotlin.
Null safety, baked into the type system.
Kotlin separates nullable and non-null references at the type level, so the “billion-dollar mistake” turns into a compile error instead of a crash.
Coroutines make async code readable.
Structured concurrency turns callbacks and raw threads into sequential, cancellable code — the runtime feature that most defines modern Kotlin.
Peer-reviewed studies on Kotlin quality, adoption, and internals · drag, use ← → or click a card
