20 Excellent Resources for Learning Kotlin

Кotlin is a modern programming language that runs on the Java Virtual Machine. It has an elegant syntax and is interoperable with all existing Java libraries. In the 2017 Google I/O, the Android team announced that Kotlin will become an official programming language for the Android platform. This puts Kotlin in position to become one of the top programming languages of the future.

To help you get started with your Kotlin journey, we've curated a list of some of the best Kotlin learning resources available right now. We haven't included any paid courses or books, everything on the list is 100% free.

The Kotlin Website

The official website for the project is a very good place to start your Kotlin education. In the reference section you can find in-depth documentation that covers all the main concepts and features of the language. The tutorials section has a variety of practical step-by-step guides on setting up a working environment and working with the compiler.

There is also the Kotlin editor, a browser app that let's you try out the language. It is loaded with many examples including the Koans course - by far the best way to get familiar with the syntax.

Keddit: Learn Kotlin while developing an Android App

An excellent 11-part series by Juan Ignacio Saravia in which he puts Kotlin into action and builds a Reddit clone app. The tutorials cover a vast number of topics ranging from setting up the workspace to using APIs and even unit testing. The code is available on GitHub.

Antonio Leiva's Blog

Antoni Leiva's blog is dedicated to all things Kotlin. It is updated weekly(ish) with high-quality tutorials and articles in which more advanced Kotlin developers can learn about new libraries and find all kinds of practical techniques.

Android Announces Support for Kotlin

The official Google blog post that explains the reasons behind the exciting announcement and why Kotlin deserves a place in the Android ecosystem. The article then goes on to give a brief preview of some of the awesome syntax improvements that Kotlin brings.

Design Patterns implemented in Kotlin

Dariusz Baciński has created a useful GitHub repo containing common design patterns implemented in Kotlin. There are similar projects written in several languages including Java, Swift, JavaScript, and PHP, so if you are coming from one of these programming background you can use them as a reference point.

Learn X in Y minutes

A quick cheatsheet with some of the most important features and syntax quirks that will help you write better Kotlin code. There are examples on working with classes, loops, and lists, as well as implementations of classic programming problems such as generating a Fibonacci sequence.

The Kotlin Blog

The official blog for Kotlin by its authors at JetBrains. Here you can find all Kotlin related news and updates, as well as all kinds of tutorials, tips, and other useful articles.

Get Started with Kotlin on Android

A helpful article from the Google Developers blog that explains how to setup Android Studio for Kotlin, how to convert .java files to .kt files, and how to incorporate the new language into an existing Android project. There are also some code comparisons on the same Android APIs used with both Kotlin and Java.

Android Testing With Kotlin

Great article that shows us how to write and run tests for Android apps using Kotlin. The author does a great job of explaining what different types of tests are available, when to use them, and how to make sure we are testing properly. Another good tutorial on this topic can be found here.

Introduction to Kotlin

A talk from Google I/O 2017 dedicated to introducing Kotlin to people for the first time and giving them an idea of how it can improve their workflow. It covers many of the basics and showcases some cool Kotlin tips.

Life is Great and Everything Will Be Ok, Kotlin is Here

The second Kotlin talk from Google I/O 2017. This one covers more advanced topics like design patterns, best practices, and other common principles. It also sheds some light on what it is like to use Kotlin in production and the challenges of adopting a young language in the workplace.

Peter Sommerhoff's Kotlin Tutorials

Here is a free Kotlin course for complete beginners that includes all the basics from variables to conditionals to loops and functions. It then goes on to more advanced topics like object-orientation in Kotlin and functional programming like lambda expressions.

Better Android Development with Kotlin & Gradle

This talk from 2016 consists of a brief overview of the language's features followed by a real world example where you'll learn how Kotlin fits in with the existing tools in a typical Android workflow.

Better Android Development with Kotlin & Gradle

A very good 8-minute tutorial that quickly goes over the most important Kotlin features, such as the shortened variable declarations, lambdas, extension function, and more.

Android Development with Kotlin — Jake Wharton

Introduction to Kotlin that explains how the new language will improve the Android ecosystem and shows us a number of cool ways we can use the smart Kotlin syntax to our advantage.

From Java To Kotlin

Useful cheatsheet containing short snippets of code that will help you quickly look up the Kotlin alternatives to common Java operators, functions, and declarations.

Kotlin Educational Plugin

A plugin for IntelliJ IDEs that allows you to take the Koans course in a local offline environment.

Kotlin on GitHub

Kotlin has been open-source for more than 5 years and there is a GitHub repo containing the entire history of the project. If you want to support the language there are multiple ways you can contribute, be it directly or by working on the docs.

Kotlin Android Template

Template Android project that makes it super easy to setup a stable Kotlin workspace and quickly bootstrap your apps.

Awesome Kotlin

An extensive list of Kotlin resources containing all sorts of useful links, books, libraries, frameworks, and videos. The list is very well organized, with a stylized version also available at kotlin.link.