lightbulb_outline Please take our October 2018 developer survey. Start survey
Kotlin and Android

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.

Download

Android KTX

Android KTX makes Android development with Kotlin more concise, pleasant, and idiomatic by leveraging Kotlin language features.

Learn more

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.

See documentation

Learning resources

Explore a curated set of resources in various formats to help you jumpstart learning Kotlin.

See resources

What does Kotlin code look like?

What does Kotlin code look like? Nullable and NonNull types help reduce NullPointerExceptions, lambdas can be used for concise event handling code, template expressions can be used in strings to avoid concatenation and semicolons are optional.What does Kotlin code look like? Nullable and NonNull types help reduce NullPointerExceptions, lambdas can be used for concise event handling code, template expressions can be used in strings to avoid concatenation and semicolons are optional.What does Kotlin code look like? Nullable and NonNull types help reduce NullPointerExceptions, lambdas can be used for concise event handling code, template expressions can be used in strings to avoid concatenation and semicolons are optional.

Apps built with Kotlin

Many apps are already built with Kotlin—from the hottest startups to Fortune 500 companies.

  • Slack
  • Lyft
  • Robinhood
  • Evernote
  • Square
  • Deliveroo
  • Periscope
  • Udacity
  • Instacart
  • Pinterest
  • Basecamp
  • Pocket
  • Reddit
  • Camera360
  • Trello
  • Foursquare
  • Stride
  • Amex
  • Expedia
  • Netflix
  • Kindle
  • Keepsafe
  • NYTimes
  • Nova Launcher
  • Wordpress
  • Simple
  • Twitter
  • Airbnb
  • Flipboard
  • Foursquare Swarm
  • WeChat
  • GO-JEK
  • Confluence Cloud
  • Zola Sales
  • Juno
  • Adobe Acrobat Reader

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

Take the interactive tutorials for Kotlin right in your web browser.

Official Language Reference

Start learning Kotlin from the official language reference site.

Kotlin Bootcamp for programmers

Udacity course created by Google to help you jumpstart learning Kotlin.

Android + Kotlin on Medium

Technical articles on Kotlin from the Android team.

Android Codelabs in Kotlin

Learn the latest best practices and APIs with Android Codelabs in Kotlin.