2018

Kotlin Census
2020

Introduction

This report shows the results of the Kotlin Census Survey conducted by JetBrains. We surveyed 6,696 developers at the beginning of 2020, and their answers have helped us recognize the trends, patterns, and state of our language. We now better understand the adoption of Kotlin in development teams, the methods and materials developers use to learn Kotlin, its place in college and university education, and much more.

To minimize possible bias against non-English-speaking respondents, we offered the survey in four additional languages: Chinese, French, Japanese, and Korean.

Key highlights

Kotlin has definitely matured as a language since the last Kotlin Census. There is an increase in its adoption at larger companies, in its use in production code, and it being chosen as a main language. All this indicates that there is an upward trend for using Kotlin as a language for industry and professional development. The time of experiments has gone — now it's time for achievements!

66%

of Kotlin users use the language in production, up from last year’s 57%.

56%

of respondents have chosen Kotlin as their main language, up from 39% last year.

4.43

is the mean average rating for experience with the Kotlin plugin for IntelliJ IDEA.

Developers recommend Kotlin first and foremost for Android and server-side development. Every 5th user recommends it for multiplatform development.

Use of Coroutines increased to 56% from 45% in 2018.

The geography of the respondents

11% 9% 7% 6% 6% 6% 5% 4% 3%
Show more ▼

We reached Kotlin users living in 122 different countries. “Other” includes countries with fewer than 1%.

Community Portrait

We open our report with a section describing the people in the Kotlin community. From this section you can get insights about age, years of professional experience, employment status, job roles, and many other interesting facts about the Kotlin community.

Age

18–203%21–2944%30–3937%40–4912%50–594%60 or older1%

Years of professional coding experience

Less than 1 year5%1–2 years13%3–5 years29%6–10 years25%11+ years27%I don't have any professional coding experience1%

Employment status

82% 6% 5% 4% 2% 1% 1%

Job roles

2020
2018
92%/91%19%/27%17%/22% 5%/0% 5%/6% 2%/4% 2%/2% 2%/3% 1%/2% 1%/2% 1%/1% 2%/2%

Company size

2020
2018
3%/9% 8%/13%20%/20%33%/28% 7%/6%13%/11%15%/12% 1%/2%

Target industries respondents develop for

42%21%17%14%13%10% 9% 9% 8% 8% 8%
Show more ▼

Company’s line of work

Develops own product(s)
Provides software development services
A bit of both
Other
57%25%15%3%

Size of project team

5%24%33%17%10% 6% 5%

Main programming language

2020
2018
56%/39%25%/43% 3%/3% 3%/3% 2%/3% 2%/1% 2%/0% 1%/2% 1%/0% 1%/1% 1%/1% 1%/1% 2%/4%

Additional programming languages

67%48%47%32%23%14%13%11%10%
Show more ▼

The most frequent combination of languages from 49% of respondents in this survey was Kotlin as the main programming language with Java used additionally. The second most popular combination is Java with Kotlin. The third is Kotlin with JavaScript.

Experience with using Kotlin

2020
2018
18%/20%17%/24%28%/33%32%/20% 5%/2%

User group membership

I am not a member of any user groups
I’m a member of a Kotlin User Group
I’m a member of another user group
74%18%8%

Kotlin news sources

49%30%29%21%21%17% 9% 6%17%

Adoption

This section contains insights into the behavior of the community concerning Kotlin adoption. It explores how people use Kotlin, how often they use it, why people don’t use Kotlin yet, and much more. It also covers which roles in a development team are more likely to become advocates for Kotlin, and the methods and materials respondents prefer to use for learning.

What do respondents develop in Kotlin?

2020
2018
63%/58%40%/48%17%/26% 9%/15% 5%/16% 5%/0% 5%/11%
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Platforms targeted with Kotlin

Plans to try Kotlin for other platforms

43%28%27%25%17%12%

How Kotlin is being used

2020
2018
66%/57%11%/12% 6%/5% 6%/13% 6%/10% 2%/2% 1%/0% 1%/1% 1%/0%

Inspiration to try Kotlin

62%60%59%57%44%34%33%22%15%11% 9% 8% 5% 4% 5%

Looking for inspiring stories to try Kotlin?

Check out the case studies of leading worldwide companies that use Kotlin in production.

Kotlin Multiplatfrom Mobile →
Kotlin Server Side →

Frequency of usage

33%32%14% 7% 6% 5% 3% 1%

More than half of respondents write 70% or more of their daily code in Kotlin.

Who initiates the adoption of Kotlin in teams?

72%16% 5% 4% 4%

First exposure

19%14%12%12%10% 9% 8% 6% 4% 3% 1% 4%

Helpful learning resources

2020
2018
55%/64%52%/72%52%/59%49%/51%38%/33%35%/31%34%/26%
Show more ▼

Tasks Kotlin is recommended for

81%62%18%13% 9% 7% 7% 4% 1%

Reasons for not adopting Kotlin

35%33%18%15%14%14%11%10% 4% 4% 4%
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Ecosystem

This section demonstrates what tools, frameworks, libraries, serverless technologies, and so on the Kotlin community is using.

You can also find insights on the Gradle Kotlin DSL and popularity of Kotlin usage for task automation in this section.

Main IDE for Kotlin development

2020
2018
51%/44%34%/37%14%/17% 1%/2%

90%

of respondents rated their overall experience with the Kotlin plugin as 4 or 5 out of 5.

Build tools usage

2020
2018
88%/85%29%/24%16%/14% 2%/2% 3%/2%

Do you use the Gradle Kotlin DSL?

2020
2018
42%/32%48%/68%10%/0%

Usage of JetBrains Kotlin libraries and frameworks

2020
2018
56%/45%23%/19%22%/0%19%/18% 6%/6% 5%/6%
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Most used kotlinx.coroutines features

Only Coroutines users were asked this question.

Usage of other Kotlin libraries and frameworks

2020
2018
41%/0%34%/0%28%/19%27%/27%24%/23%23%/20%21%/16%21%/11%19%/10%19%/0%
Show more ▼

Top-10 Android-specific Kotlin libraries and frameworks

78%67%59%53%44%36% 2% 3%

Do you use serverless computing?

Yes
No
26%74%

Most used language for serverless

36%33%33%30%27%19%
Show more ▼

Popularity of cloud providers

Task automation

71%58%54%17%12%11% 8% 1%

Languages used for automation scripting

40%40%32%31%28% 7% 1% 9%

56%

of respondents use 2 or more scripting languages for task automation.

Multiplatform

This section provides an overview of how the community uses Kotlin Multiplatform Projects for sharing code across platforms in the applications.

If you want to learn more about the benefits of multiplatform, please visit this section of the Kotlin website.

Do you use Multiplatform Projects for sharing your code across platforms?

Yes
No
13%87%11%89%20202018

79% of respondents would like to try Multiplatform Projects in the future.

Multiplatform Projects usage

Only Multiplatform Project users were asked this question.

74%55%48%36%20%18%16%15% 3% 1%

The most popular combinations for cross-platform apps with Kotlin Multiplatform Projects (MPP) are Android and iOS (53% of MPP users), Android and JVM (26% of MPP users), and JVM and JavaScript in the browser (26% of MPP users).

Parts of projects shared across multiple platforms

2020
2018
60%/64%49%/50%41%/39%32%/0%22%/20%21%/25%13%/7%12%/21%12%/7% 6%/6% 5%/6% 5%/3%

Kotlin Multiplatform Mobile

The natural way to share code between mobile platforms.

Create your first project using our step-by-step guide.

Application types respondents would like to try Multiplatform Projects for

64%55%30%27%20%18%18%12% 5% 1%

Kotlin Multiplatform Web

Build connected applications and share logic between the server and the client-side running in the browser.

Try it out using our step-by-step guide.

Ktor
An asynchronous framework for creating connected web applications, and more. It’s fun, free, and open source.
Check it out

Kotlin for Server-side

This section is highlighting patterns of Kotlin usage among web backend developers.

If you’re using Kotlin for server-side development or looking at Kotlin for the future, check out our Kotlin Server landing page. It contains all the essential information about Kotlin tooling, libraries, and industrial use cases.

The charts in this section are based on the answers from the respondents who checked “Web backend” in the question “What types of software do you currently develop in Kotlin?” There were 1989 answers in total.

Platforms targeted with Kotlin

JVM Server94%Android29%JVM Other19%JS10%Native8%I don't know1%

Main Kotlin development IDE

2020
2018
70%/63%20%/22%10%/13% 0%/3%
IntelliJ IDEA for Kotlin
A capable and effective IDE for the JVM and beyond.
Check it out

Build tool usage among server-side developers

2020
2018
83%/78%44%/38%15%/15% 2%/2% 1%/1%

58%

of respondents who use Kotlin for web backend development use the Gradle Kotlin DSL.

Top 10 Kotlin libraries and frameworks for web backend development

57%56%56%32%31%30%28%25%25%21%

JDK versions

2020
2018
15%/0% 8%/0%52%/30% 4%/8% 4%/7%72%/86% 3%/7% 2%/5% 1%/2%

Do you use the Java module system?

2020
2018
74%/74%17%/17% 8%/9%

Do you use Multiplatform Projects for sharing code across platforms?

No
Yes
88%12%

Kotlin for Web Frontend

At the moment, according to our analytics, there are over 12,000 projects using Kotlin/JS. As the number of Kotlin use cases for web development with Kotlin is so significant, we just had to dive into the data to learn how exactly respondents are using Kotlin/JS, where they run JavaScript code compiled from Kotlin, and which libraries and frameworks they prefer.

97% of respondents use Kotlin/JS together with Kotlin on the server side of their web applications.

The charts in this section are based on the answers from those respondents that checked “Web Frontend” to the question “What types of software do you currently develop in Kotlin?” There were 255 answers in total.

Platforms targeted with Kotlin

JVM Server84%JS51%Android45%JVM Other27%Native21%I don't know1%

Purpose of Kotlin/JS usage

Kotlin/JS build approach

52%25%23%15% 5% 9%

Most popular UI frameworks

React52%Angular15%Vue.js11%Web Components8%Polymer2%Other16%None24%

Do you use Multiplatform Projects for sharing code across platforms?

No
Yes
57%43%

The most popular combinations of platforms for code sharing are JVM and JavaScript in the browser (69%) and Android and JavaScript in the browser (34%).

Kotlin in Universities

Over 2019–2020, Kotlin has grown as a language of choice for many educators at universities, colleges, and schools.

We’ve asked a few questions about Kotlin in education and are happy to share insights gained from the Kotlin Census here.

Does your university / school / college offer one or more Kotlin courses?

Places where Kotlin is taught

Kotlin Census 2020 Raw Data

These infographics include only the most interesting facts. You are welcome to dig deeper into the raw data and find more insights if you are interested:

Download Raw Data

The data has been anonymized, with no personal information or geolocation details. To prevent the identification of any individual respondents by their verbatim comments, all open-ended fields have been shortened.

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