When you're looking for an Android app developer, it quickly becomes clear that Java is no longer in fashion. Developers will definitely ask why Java, and whether Kotlin is being considered. What kind of language is this, how did it so quickly enter the developer ecosystem, and should you learn it — read on.

The language was created by JetBrains in 2011, with an official release in 2016. Despite its novelty and many advantages, Kotlin remained in the shadows until 2017. That year, at the Google I/O conference, Kotlin was announced as the preferred language for Android development. Many industry giants have since moved their products to Kotlin — not only Google, but also Twitter and Netflix. That alone speaks volumes about its power and relevance.

Kotlin isn't so much a new language as it is the missing tool developers had been waiting for. It’s a product born out of community demand, and the creators were very responsive. They built on the strong foundation of JavaScript and created a way for developers to work faster, simpler, and more efficiently.

Kotlin was designed with one main goal — functional programming. It's significantly simpler than Java or C++, without many of their key drawbacks. But don’t expect it to be a universal solution — there’s no such thing. It’s an effective tool for a specific set of tasks, all related to Android development.

Pros and Cons

Kotlin is meant to work anywhere Java does. It can partially replace it or be used in hybrid projects. What's good about Kotlin:

Overall, Kotlin is much simpler than Java, allowing for faster and cleaner development.

And the drawbacks:

The language is most often used for mobile app development, cross-platform programming, backend development, and web development. Learn more about how frontend gets data in the online premiere “Learning to Work with Servers in JavaScript”.

Currently, the creators are building more tools and libraries, fixing known issues, and preparing educational content. So you can expect major improvements in the near future.

Do You Need It?

Let’s get to the main question — do you need Kotlin? The answer is clear: if you’re working on Android apps, then yes, absolutely start learning it. Even having a basic understanding will be useful for your overall development as a programmer.

Knowing Kotlin helps you land jobs and gigs, even if the client isn't specifically asking for it. A developer with Kotlin in their stack comes across as someone who’s staying on top of trends and leveling up their skills. It makes you stand out — or at least not fall behind.

Naturally, if you want to work with Kotlin, you'll need portfolio pieces. No one will take your word for it — you’ll need to prove it. These don’t have to be real-world projects at first — create your own app. For more on building a great resume, check out the article “How to Build a Portfolio Employers Actually Want”.

Learning

Learning Kotlin is extremely easy if you already know Java. The basics are the same, but everything is more logical and concise, without the excess. Usually, a couple of guides and a bit of practice are enough to start building simple projects. For an experienced dev, picking up Kotlin takes just a few days.

We recommend starting with the book by D. Jemerov and S. Isakova “Kotlin in Action.” It dives into the language’s features, benefits, comparisons with Java, and shows how to use them together effectively.

But be aware: learning Kotlin without a foundation is tough. Even though it’s simplified, it still requires a strong grasp of programming concepts. Starting with Kotlin is like jumping into surgery without going to med school. If you're a beginner, first learn the basics of Java. Plus, Kotlin compiles into JVM bytecode, so learning it without knowing Java just doesn’t make sense — you’ll eventually need to learn JavaScript too.

For that, check out our free course “JavaScript: Deep Dive”. It’s a great starting point for anyone new to development. The course will help you:

Start your journey into a new profession — completely free!