Assembly Line

Kotlin

The Kotlin Programming Language.

Kotlin is an open-source programming language project on GitHub under a license set out in its repository, with 54k stars. It is built with JDK. Its last push was today.

Stars
54k
License
See repository
Activity
Active
Latest release
v2.4.21

Code on GitHub Website

Judgement

What it is
Developer tool
What it does
The Kotlin language and compiler from JetBrains, targeting the JVM, Android, native code and WebAssembly, and the main language for Android.
Adopt it when
You build Android apps or JVM services and want a more concise, null-safe alternative to Java.
Watch out
Compile times can be slow on large projects, and multiplatform targets beyond JVM are less mature.
Ready for
Production-ready
Runs as
Command line
Built with
Kotlin and Java
How established
Established: started 14 years ago, latest release v2.4.21.
What the license allows
GitHub could not read the license. Check it in the repository before reusing any code.

Judged on 2026-11-03 from the project's README and GitHub data. The license and age lines are worked out directly.

Built from

JDK

Follow it down: Kotlin → JDK → LLVM project → runs on a microchip

How compilers were built, back to punched paper tape

Built on Kotlin: 46 projects

  1. 1
    Quarkdown iamgio

    🪐 Markdown with superpowers: from ideas to papers, presentations, websites, books, and knowledge bases.

    Developer tool Usable You write papers, books or presentations and want Markdown with LaTeX-like layout control.

    ★ 16k GPL-3.0 Kotlin Active, pushed yesterday
  2. 2
    ImageToolbox T8RIN

    🖼️ Image Toolbox is a powerful app for advanced image manipulation. It offers dozens of features, from basic tools like crop and draw to filters, OCR, and a wide range of image processing options

    Complete system Production-ready You want one free Android app for nearly every image manipulation task.

    ★ 15k Apache-2.0 Kotlin Active, pushed today
  3. 3
    Ktor ktorio

    Framework for quickly creating connected applications in Kotlin with minimal effort

    Framework or platform Production-ready Your team writes Kotlin and wants a lightweight, coroutine-based server or a multiplatform HTTP client.

    ★ 15k Apache-2.0 Kotlin Active, pushed today
  4. 4
    LangChain4j langchain4j

    LangChain4j is an idiomatic, open-source Java library for building LLM-powered applications on the JVM. It offers a unified API over popular LLM providers and vector stores, and makes implementing tool calling (including MCP support), agents and RAG easy. It integrates seamlessly with enterprise Java frameworks like Quarkus and Spring Boot.

    Framework or platform Production-ready You are adding LLM features to a Java or Kotlin application and want to stay on the JVM.

    ★ 13k Apache-2.0 Java Active, pushed today
  5. 5
    Pkl apple

    A configuration as code language with rich validation and tooling.

    Developer tool Usable Your configuration has grown large enough that plain YAML causes mistakes and you want validated, reusable config.

    ★ 12k Apache-2.0 Java Active, pushed today
  6. 6
    RikkaHub rikkahub

    RikkaHub is an Android APP that supports for multiple LLM providers.

    Complete system Usable You want one Android app for chatting with several AI providers using your own API keys.

    ★ 8.6k AGPL-3.0 Kotlin Active, pushed today
  7. 7
    Javalin javalin

    A simple and modern Java and Kotlin web framework

    Framework or platform Production-ready You want a small, readable web layer for a JVM service without Spring's weight.

    ★ 8.4k Apache-2.0 Kotlin Active, pushed 2 days ago
  8. 8
    Jev-chat-jarvis jev-chat

    The chat decision assistant: before you reply, Jev reads the chat, judges intent and risk, and drafts replies you fill in with one tap. You press send. Android · Windows · macOS · iOS | 聊天辅助决策工具：先看懂对方再回复，发不发由你。

    ★ 8.2k MIT Kotlin Active, pushed yesterday
  9. 9
    ReadYou ReadYouApp

    An Android RSS reader presented in Material You style.

    Complete system Usable You want a good-looking free feed reader on Android.

    ★ 7.6k GPL-3.0 Kotlin Active, pushed 3 months ago
  10. 10
    KeePassDX Kunzisoft

    Lightweight vault and password manager for Android, KeePassDX allows editing encrypted data in a single file in KeePass format and fill in the forms in a secure way.

    Complete system Production-ready You keep passwords in a KeePass file and need an Android app that reads and writes it.

    ★ 7.6k GPL-3.0 Kotlin Active, pushed yesterday
  11. 11
    Android-DataBackup XayahSuSuSu

    DataBackup for Android 7.0+

    Complete system Usable Your Android phone is rooted and you want full app-plus-data backups when switching ROMs or devices.

    ★ 7.6k GPL-3.0 Kotlin Active, pushed 9 days ago
  12. 12
    PlainApp plainhub

    🔥 PlainApp is an open-source app that lets you securely manage your phone from a web browser. Access files, media, contacts, SMS, calls, and more through a simple, easy-to-use interface on your desktop.

    Complete system Usable You want to move files and handle messages on your Android phone from your computer without cloud services.

    ★ 7.1k AGPL-3.0 Kotlin Active, pushed today
  13. 13
    Alda alda-lang

    A music programming language for musicians. :notes:

    Developer tool Usable You are a musician or programmer who wants to write music in a text editor.

    ★ 6k EPL-2.0 Go Active, pushed 10 days ago
  14. 14
    FXGL AlmasB

    Java / JavaFX / Kotlin Game Library (Engine)

    Framework or platform Usable You teach or learn game development in Java, or already use JavaFX.

    ★ 4.9k MIT Kotlin Active, pushed 17 days ago
  15. 15
    Android home-assistant

    Home Assistant Companion for Android

    Complete system Production-ready You run Home Assistant and use Android devices.

    ★ 4k Apache-2.0 Kotlin Active, pushed today
  16. 16
    Apps-android-wikipedia wikimedia

    📱The official Wikipedia app for Android!

    Complete system Production-ready You read Wikipedia on Android, or want to study a large, well-run open-source Android codebase.

    ★ 3.1k Apache-2.0 Kotlin Active, pushed today
  17. 17
    Blockads-android pass-with-high-score

    Block ads system-wide on Android using local VPN-based DNS filtering. No root needed. No data collection.

    Complete system Usable You want system-wide ad and tracker blocking on an unrooted Android phone from a free open-source app.

    ★ 2.6k GPL-3.0 Kotlin Active, pushed today
  18. 18
    Twine msasikanth

    Twine: A multiplatform RSS reader built using Kotlin and Compose

    Complete system Usable You want one good-looking feed reader that works the same on Android, iPhone and desktop.

    ★ 2.4k GPL-3.0 Kotlin Active, pushed today
  19. 19
    HTTP-Shortcuts Waboodoo

    Android app to create home screen shortcuts that trigger arbitrary HTTP requests and more

    Complete system Production-ready You want one-tap phone buttons for webhooks, home automation endpoints or your own APIs without writing an app.

    ★ 1.9k MIT Kotlin Active, pushed today
  20. 20
    Capyreader jocmp

    A smallish Android RSS reader

    Complete system Usable You want a tidy, actively maintained Android reader that works with your own feed server.

    ★ 1.4k GPL-3.0 Kotlin Active, pushed today

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  1. 1
    Go golang

    The Go programming language

    Developer tool Production-ready You build backend services or command-line tools and value simple code, fast builds and single-binary deploys.

    ★ 140k BSD-3-Clause Go Active, pushed today
  2. 2
    Rust rust-lang

    Empowering everyone to build reliable and efficient software.

    Developer tool Production-ready You need C-level performance with memory safety, for systems software, CLIs, services or WebAssembly.

    ★ 121k Apache-2.0 Rust Active, pushed today
  3. 3
    TypeScript microsoft

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

    Developer tool Production-ready You write JavaScript projects of any size and want static types and better editor tooling.

    ★ 112k Apache-2.0 Go Active, pushed today
  4. 4
    CPython python

    The Python programming language

    Developer tool Production-ready You write Python, or need to build, embed or contribute to the interpreter itself.

    ★ 78k See repository Python Active, pushed today
  5. 5
    Swift swiftlang

    The Swift Programming Language

    Developer tool Production-ready You build iOS or macOS apps, or want Swift on Linux servers.

    ★ 71k Apache-2.0 Swift Active, pushed today
  6. 6
    Julia JuliaLang

    The Julia Programming Language

    Developer tool Production-ready You do scientific computing, simulation or numerical work where Python is too slow and C is too painful.

    ★ 49k MIT Julia Active, pushed today
  7. 7
    Php-src php

    The PHP Interpreter

    Developer tool Production-ready You build or host PHP applications, or need to build PHP or its extensions from source.

    ★ 42k BSD-3-Clause C Active, pushed today
  8. 8
    LLVM project llvm

    The LLVM Project is a collection of modular and reusable compiler and toolchain technologies.

    Developer tool Production-ready You compile C or C++ with Clang, or are building a compiler or language tooling.

    ★ 41k See repository LLVM Active, pushed today

Stars, license and activity come from GitHub and refresh on a rolling hourly schedule. The project's own description is quoted as written.