Kotlin is Google's preferred language for Android and a clean, modern choice for backend work too, and JetBrains plus Google give away excellent official material for free. Work through Kotlin Koans and the official docs, then build a real Android app with Google's free courses and codelabs.
JetBrains' own free learning track with real world projects and coding challenges, taught by the creators of Kotlin.
Google's free course teaching programming fundamentals and Kotlin from zero using Jetpack Compose.
Free self paced Google backed course covering Kotlin fundamentals for people who already know another language.
The same Google Kotlin bootcamp content hosted on Google's own Digital Garage platform.
A full multi hour beginner course published free on freeCodeCamp's site and YouTube.
An extensive free hands on course that builds multiple real Android apps from Kotlin fundamentals up.
An official Google two unit course building five real Android apps while teaching architecture components.
Free step by step beginner course with practical examples and no prior experience required.
The official Kotlin YouTube channel with tutorials, Kotlin Multiplatform content, coroutines and the Talking Kotlin podcast.
A structured YouTube playlist walking through Kotlin basics aimed at Android learners.
A single video freeCodeCamp Kotlin course for beginners on YouTube.
A free 12 hour comprehensive Android development course taught with Kotlin.
An active well regarded channel focused specifically on native Android, Kotlin Multiplatform and backend Kotlin.
Video version of the official Kotlin podcast, covering language features and community projects.
The official JetBrains entry point for setting up and writing your first Kotlin code.
The full official Kotlin documentation hub covering every language feature.
An official guided tour that quickly covers Kotlin fundamentals in sequence.
A large hub of practical well written Kotlin tutorials covering everything from basics to Spring integration.
A solid single article introduction to classes, null safety, data classes and more.
A free thorough written tutorial covering basic through advanced Kotlin topics.
A beginner friendly tutorial with a built in try it yourself code editor.
A roadmap style article aimed specifically at using Kotlin for Android development.
Google's official landing page pointing Android learners to the right Kotlin learning path.
JetBrains' official set of syntax exercises where you fix failing unit tests to learn Kotlin idioms.
A browser based version of Kotlin Koans, no install needed.
The source repository for Kotlin Koans, usable inside IntelliJ IDEA or Android Studio.
A free track with dozens of exercises, automatic code analysis and free human mentoring.
A curated repository of Kotlin coding puzzles with solutions for self practice.
Free kata style coding challenges in Kotlin ranked by difficulty.
Short practice exercises with answers for reinforcing basic Kotlin syntax.
A set of exercises covering basics, control flow, OOP and collections with sample solutions.
Official Google practice problems reinforcing the Android Basics Kotlin fundamentals course.
The complete official Kotlin docs bundled into one downloadable PDF.
A directory linking to multiple free downloadable Kotlin books and lecture notes.
A free community compiled book built from curated Stack Overflow documentation content.
A free unofficial ebook compiled for educational purposes, also downloadable directly as a PDF.
A free resource offering clear concise explanations aimed at programmers new to Kotlin.
Free sample chapters of the well regarded Atomic Kotlin book by Bruce Eckel and Svetlana Isakova.
JetBrains' official hub of free learning materials, courses and university content for teaching Kotlin.
Google's free official IDE for building Android apps in Kotlin, including AI assisted coding tools at no cost for individuals.
The official browser based Kotlin editor and compiler, no install required.
A free fast online Kotlin compiler good for quick experiments and sharing code.
A simple in browser Kotlin compiler paired with Programiz's tutorial content.
A free general purpose online IDE that supports running Kotlin code directly in the browser.
A free browser based Kotlin IDE with autocompletion, multi file support and a terminal.
The official Kotlin podcast from JetBrains, covering language features, Kotlin Multiplatform and community projects.
The Apple Podcasts listing for the official Kotlin podcast, free to stream or download.
Google's official Android developer podcast and video series covering recent releases and libraries relevant to Android devs.
A long running well known Android developer podcast covering testing, dependency injection, patterns and libraries.
A free downloadable PDF cheat sheet focused on Kotlin best practices from a respected Kotlin educator.
A well known two page PDF quick reference covering Kotlin syntax essentials.
An interactive online quick reference with runnable usage examples for common Kotlin syntax.
A free community made PDF cheat sheet covering Kotlin syntax at a glance.
JetBrains' official hub linking to Slack, Reddit, Stack Overflow and other Kotlin community spaces.
The official Kotlin discourse forum used for language and tooling discussion, including how to join the Slack.
The official sign up form to join the active kotlinlang Slack developer community.
A public searchable archive of the official Kotlin Slack conversations, useful even without joining.
A free progressively structured set of 25 real Android projects for hands on practice, from a todo app to Compose apps.
A repository of absolute beginner friendly Kotlin Android projects to build from scratch.
Small practice projects for reinforcing Android basics with Kotlin.
JetBrains' own repository of varied Kotlin code examples across different use cases.
A free guided project for building a real cross platform Android and iOS app with Kotlin Multiplatform.
Google's course embedded real app projects for building UI, navigation and lists as you learn.