Develop Android apps with Kotlin
Write better Android apps faster with Kotlin. Kotlin is a modern statically typed programming language that will boost your productivity and increase your developer happiness.
Modern and expressive
Kotlin's modern language features allow you to focus on expressing your ideas and write less boilerplate code. Less code written also means less code to test and maintain.
Safer code
Improve your app quality with Kotlin. @Nullable and @NonNull types are baked into Kotlin's type system to help you avoid NullPointerExceptions. Kotlin also has many other language features to help you avoid common programming mistakes.
Interoperable
Call Java-based code from Kotlin, or call Kotlin from Java-based code. Kotlin is 100% interoperable with the Java programming language, so you can have as little or as much of Kotlin in your project as you want.
Optimized for Kotlin
Kotlin is production-ready for your Android app development.
Android Studio
Android Studio provides first-class support for Kotlin. It even has built-in tools to help you convert Java-based code to Kotlin. The Show Kotlin Bytecode tool lets you to see the equivalent Java-based code as you learn Kotlin.
Android KTX
Android KTX makes Android development with Kotlin more concise, pleasant, and idiomatic by leveraging Kotlin language features.
Kotlin-friendly SDK
Starting with Android 9 (API level 28), the Android SDK contains nullability annotations to help avoid NullPointerExceptions. API reference documentation is also available in Kotlin.
Note: Many Kotlin reference topics are derived from Java-based source code. This means that some Kotlin reference topics might contain Java code snippets.
Learning resources
Explore a curated set of resources in various formats to help you jumpstart learning Kotlin.
What does Kotlin code look like?
Kotlin Bootcamp for programmers
Udacity course created by Google to help you jumpstart learning Kotlin.
Apps built with Kotlin
Many apps are already built with Kotlin—from the hottest startups to Fortune 500 companies.
Zomato uses Kotlin to write safer, more concise code
Kotlin helped Zomato reduce the number of lines of code in their app significantly, and it has also helped them find important defects in their app at compile time.
Watch Zomato's Rahul, Vice President, Product Management, and Prateek Sharma, Android Developer, talk about how Zomato started adopting Kotlin and about how they now use it for all new feature releases.
Kotlin is free and open
Kotlin is a free and open source project under the Apache 2.0 license. Its development and distribution as free software is secured by the Kotlin Foundation. Our choice of Kotlin reaffirms our commitment to an open developer ecosystem as we evolve and grow the Android platform, and we are excited to see the language evolve.
Featured resources
Try Kotlin
Official Language Reference
