What is Kotlin used for? What’s worth knowing?

Marlena Walburg
What is Kotlin used for - What_s worth to know

Observing the world of technology today, it is not difficult to notice that every now and then, a new approach, programming language or framework appears. This strongly influences both trends and far-reaching development. Looking at the statistics on the most wanted programming languages among developers worldwide, we can clearly see that Kotlin’s meaning is getting bigger. You may ask yourself at this point, what is Kotlin for or is it worth considering in such a case. We hurry to tell you all about it.

It is undoubtedly a technology that quickly became a hit, and its creators are not afraid to experiment with adding new features. It has gained enormous interest among developers, especially after Google announced in 2017 that it would support it as the official language of Android applications. Currently, it is not only praised by them and even recommended in the development process of Android applications. It is about the enormous success of Kotlin, but also about its quality. Get to know the details about it and find out what advantages it can provide you.

What is Kotlin?

Kotlin is an open-source, cross-platform, general-purpose programming language. Kotlin is designed to interoperate fully with Java. The JVM version of Kotlin’s standard library depends on the Java Class Library, but type inference allows its syntax to be more compact. Kotlin mainly targets the JVM but also compiles to JavaScript or native code. In general, it requires fewer lines of code to achieve similar results. At the same time, Kotlin is entirely compatible with Java, which gives a possibility to convert from Java to Kotlin or create interactions between these codes. The creators of Kotlin pride themselves on that it was designed to avoid entire classes of errors such as null pointer exceptions. Besides, it is primarily a tool that facilitates and accelerates the work of developers, without sacrificing application performance or code quality.

What can Kotlin do for your business?

As a general-purpose language, Kotlin is used to write software in the widest variety of application domains. It is mostly used for native Android mobile development, though. Moreover, since 2019, it is even preferred by Google for writing applications for this platform. Kotlin enables app development with less time and effort put in the process. It’s more concise – it is roughly estimated to reduce the amount of code by up to 40% compared to Java. Simpler and easier to understand code results in greater resistance to errors, and when they eventually occur, they will be effortless to detect and fix. Fewer lines of code and increased protection against bugs also save a lot of money from the project budget and make further maintenance more pleasant and convenient. The versatility of Kotlin makes it ready for you to transfer your application from one platform to another if necessary. Also, do not forget that Kotlin’s attractiveness appeals to new, better developers. If you want to have the best specialists, up-to-date with the newest technology onboard, consider choosing Kotlin for your application. 

Important features of Kotlin

What is Kotlin’s greatest strength is not only Google’s support, but also the benefits of implementing it into your project. There is a reason why so many companies are adapting to this Kotlin or switching to it completely. It’s already a trusted technology. Take a closer look at the most essential benefits of Kotlin.

Fully compatible with Java

Kotlin is completely interoperable with Java. Kotlin’s creators have made sure that the existing codebase can work properly with it. Kotlin developers have access to all Java libraries and features, but at the same time, they write more concise code. They can easily call Kotlin code from Java and vice versa. This makes adoption much easier and less risky. To simplify the migration of existing code, there is also an automatic Java-Kotlin converter built into the IDE.

Learn more about Java on our blog:

More safety

One of the most common pitfalls in many programming languages, including Java, is that accessing a null reference member will result in a null reference exception. That’s because the variable that doesn’t refer to anything refers to null. In Java, this would be the NullPointerException or NPE equivalent for short. The Kotlin type system is designed to eliminate the hazard of null reference from code. Frequent checking for null values is annoying, but if you need to allow their use, Kotlin has some very useful operators to make it easier.

Multi-platform development

Kotlin can be used for any type of programming, be it a server-side, client-side network, or Android. It is JVM compatible and therefore allows you to use any existing framework such as Spring Boot. In addition to the back-end, Kotlin can use definitions from DefinitelyTyped to get static typing for common JavaScript libraries to build client-side of web development. For native programming, it is still in beta, but there is a Kotlin compiler for native code that works without a virtual machine.  

Kotlin requires less coding

We have said it many times above that Kotlin helps to reduce the volume of code without losing its quality and efficiency. Importantly, the code written in Kotlin does not lose its readability. Also, of course, we limit the risk of bugs. All this to facilitate the application development process. This is one of the biggest advantages both in business meaning and for the developers themselves. 


A large, dedicated community behind any framework is not only a guarantee of support but also the further development of a given technology. Kotlin also boasts an engaged group of users sharing knowledge and inspiration. This group is constantly growing, as well as new sources of information about the Kotlin.

Where to use Kotlin?

Considering that it’s a multi-platform language, it gives us many possibilities of use. However, the most popular option is Android applications. Lots of apps are already built with Kotlin – from the hottest start-ups to Fortune 500 companies.

Popular Android apps made with Kotlin

From Google’ official website for developers, we can learn that over 70% of the top 1000 Android apps use Kotlin. This is a huge number! We can find many well-known brands among them. This shows not only that Kotlin has become extremely trendy, but also highly appreciated for its advantages. Some of the most recognizable of them are:


Slack is a well-known business communication platform. It allows organizing conversations by topics, projects, or anything else that is needed. It also enables sharing and editing documents, integrating useful tools and customizing notifications. Its Android version of the app is built by a mix of Java and Kotlin.


Netflix does not need any introduction. The most popular streaming platform adapts many new technological solutions. We already mentioned this in Introduction to Microservices that Netflix has moved from a monolithic architecture to a cloud-based microservices. In 2018 they rewrote the Netflix’s player UI using a new architecture based on Kotlin and RxJava, that allows great reusability, testability and extendability.


TripAdvisor is an extremely popular travel platform. It operates as a website but also offers a mobile app for vacation rentals owners. In a similar time to Netflix, it has been slightly improved by converting some of the code to Kotlin. Tripadvisor developers were thrilled with Kotlin’s features and the ability to reduce code size, thus lessening bugs and lowering maintenance costs. 


Confluence, designed with remote access in mind, is developed by Australian software company Atlassian. It’s a workspace where teams can share knowledge and cooperate. Atlassian wrote Confluence in the Java programming language and first published it in 2004. When it comes to their mobile products, e.g. Confluence Cloud, they’ve based them on Kotlin. Atlassian’s Mobile Team Lead, Carlos Khatchikian, says they are adapting fast to the ongoing technologies and so currently, they code mobile apps Swift and Kotlin.

Learn more about Swift in our related articles:


What could be hidden under this, anyway, simple name? Banking mobile application. Simple is one of the first apps of this type, launched in 2012. Since then, it has been getting regular updates and new features. You can read about the app on Google Store that “Every aspect of a Simple checking account is optimized for branchless online banking, budgeting, and saving, so you can track spending and manage your money wherever you happen to be. Simple is personal finance made easy.” Kotlin also contributed to the good operation, thanks to which the application is much easier to maintain and, above all, safer, which is especially important in banking apps.


Conclusions as to whether it is worth using Kotlin are obvious. It is a forward-looking and reliable language. The strong connection to Java makes it easy to learn for most developers, especially those working in this technology. The growing user community is a powerful support in this regard. Considering also the positive impact and business benefits, it is a good choice for enterprises planning to develop a mobile application, as well as for those who want to modernize their current, perhaps already a bit outdated and buggy application. Regardless of your intentions, Kotlin has the potential to bring you a huge profit. When you want to outsource a company to a Kotlin project, don’t forget to ask about their previous projects to see what they can achieve with this technology.

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