These questions were only shown to respondents who chose Kotlin as one of their three primary programming languages.


What do you use Kotlin for?

The majority of Kotlin developers still use the language for developing Android and server-side applications. More than 10 percent use Kotlin for mobile multiplatform development, and this number continues to grow.

Since Kotlin is a multiplatform language, it is also used by significant numbers for other types of software development and data science.

JDK 8 is still the most popular version among Kotlin developers (64%) even though it has lost 10 percentage points since last year. Kotlin supports all new versions of JDK, including JDK 16.

What JetBrains Kotlin libraries and frameworks do you currently use?

A greater proportion of Kotlin developers are using libraries and frameworks in 2021 than before.

The popularity of the top Kotlin libraries created by JetBrains is increasing. Coroutines, the most popular library, has increased its share by 10 percentage points since last year.

Serialization and Test have raised their presence by 9 and 6 percentage points respectively. In their tasks, roughly a quarter of Kotlin users apply Ktor, an asynchronous framework for creating microservices, web applications, and more.

What other Kotlin libraries and frameworks do you currently use?

Spring/Spring Boot, which in 2018 was the most-used non-JetBrains framework, now ranks third behind Gson and Jackson.

Check out this video overview to find out more about Spring, Coroutines, and reactive programming.

How long have you been using Kotlin?

The average Kotlin developer is becoming more experienced and is growing together with the language. In 2018, more than half of the Kotlin developers had used the language for less than 6 months. And now a plurality of 31% are developers who have been using Kotlin from 2 to 4 years.

What do you use Kotlin for?

What types of projects do you primarily use Kotlin for?

What languages did you use before you switched to Kotlin?

How did you learn Kotlin?

If you are interested in learning more about Kotlin, there are some great learning resources from the language creators available, including the Get started with Kotlin website, the Kotlin YouTube channel, and the book “Atomic Kotlin”.

Which IDE do you use most regularly for Kotlin development?

To learn more about the state of the Kotlin language, check out our official Kotlin Census Report.

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