For years, Java has been the standard for developing Android apps. In 2011, JetBrains presented Kotlin, a new statically-typed language running on Java Virtual Machine. In 2017, during Google I/O, Kotlin was announced as an official language for Android development.
As Kotlin is a modern programming language with powerful features, it gained popularity among Android developers. It was placed second on the list of the most loved programming languages in the Stack Overflow Developer Survey 2018.
However, developers’ preferences do not always reflect business reality. Is Kotlin mature enough to be used in production? Is there any ‘social proof’ that successful commercial apps can be written in Kotlin?
Here is a list of 10 great Android mobile apps written in Kotlin. Some of them have been developed by top companies and have had millions of downloads from Google Play, while others are popular open-source projects appreciated by developers.
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The famous photo-sharing social service decided to use Kotlin and move away from Java in their Android app. They presented the pros and cons of using Kotlin in production at Droidcon NYC 2016. What might seem a little shocking is that Kotlin was used in such a popular app with its massive user base even before Google announced the first-class support for this language.
100,000,000+ downloads from Google Play, average rating 4.6 from 6,935,805 reviews.
Coursera is an educational company providing open online courses conducted by remarkable universities and institutes such as Stanford and Yale. Coursera doesn’t have separate Android and iOS organizations. They only have the concept of mobile and that’s why they decided to start using Kotlin. Kotlin is similar to Swift, a relatively new programming language for iOS development. This results in easier knowledge sharing between engineers, better communication, and more efficient overall development.
10,000,000+ downloads from Google Play, average rating of 4.4 from 116,493 reviews.
Trello is a well-known project-management application, currently owned by Atlassian. For their Android app, the new code is written in Kotlin. However, they're not going to do a full code conversion of the old codebase. Working with Java and Kotlin at the same time is possible thanks to the great interoperability between the two languages.
10,000,000+ downloads from Google Play, average rating of 4.4 from 95,691 reviews.
Evernote is an app designed for note-taking, organising, task lists, and archiving. Evernote integrated Kotlin into their Android client. A little more about the technical details of their adventures with Kotlin integration can be found on Evernote’s blog.
100,000,000+ downloads from Google Play, average rating of 4.2 from 1,569,650 reviews.
An app that helps manage growing small businesses. It's written fully in Kotlin and Basecamp’s developers claim that choosing Kotlin resulted in a huge difference in their work comfort, quality, and speed.
500,000+ downloads from Google Play, average rating of 4.2 from 4,229 reviews.
Open-source, 100-percent material design Twitter browser, enhancing Twitter user experience. It has been written mainly in Kotlin, although there is some Java code.
1500,000+ downloads from Google Play, average rating of 4.0 from 13,497 reviews. 2,183 stars on Github.
A high-performance cross-platform secured socks5 proxy. It helps to increase privacy and security while browsing the internet. The Android client is open-source and written in Kotlin. Shadowsocks is appreciated both by users on Google Play and other developers.
1,000,000+ downloads from Google Play, average rating of 4.4 from 62,310 reviews. 5,000 stars on Github.
A simple, fully open-source calendar with no ads or unnecessary permissions. Simple Calendar is one in a bigger set of apps: Simple Mobile Tools. All of them are open-source and written fully in Kotlin.
1,000,000+ downloads from Google Play, average rating of 4.5 from 14,598 reviews. 2,209 stars on Github.
KotlinConf is a developers’ conference, hosted by Kotlin’s creators, JetBrains. There is no way that the official conference application could be written in a different language. What is really interesting is that not only is the Android client written in Kotlin but also the web, server, and iOS application. This only goes to show the great potential of this language.
2,484 stars on Github.
DroidKaigi is a developer-first Android conference organised in Tokyo. It's another conference app developed in Kotlin to add to the list, but this time it is not a conference organised by the language creators. It's a sign of Kotlin’s popularity among Android developers.
1,309 stars on Github.
Kotlin is still relatively new, but it has already been used by top companies in their Android apps. There are also open-source projects, appreciated by developers, and all this proves that you can use the language successfully in Android applications.
Although Java is here to stay, if you are planning to develop an Android App or you already have an existing product, you should definitely keep an eye on the programming language created by JetBrains, because it can boost your team’s productivity and save you from many bugs that could easily emerge in a vanilla Java project.
All the presented data was up-to-date as of 15/03/2018.