Updated May 29, 2024

Kotlin in Japan - Language Guide


Japan Dev Team

Japan Dev contributor

Introduced in 2011, Kotlin is certainly one of the more popular languages out there today.

Thanks to its versatility and its interoperability with Java, the general-purpose, statically typed language is among the top 20 programming languages in the world today and is widely embraced by the Android development community. 

So, how are things for Kotlin in Japan? Does the high-level programming language have the same level of popularity here as elsewhere? These are only some of the questions I’ll answer in this post.

I’ll also tell you how feasible it is to learn Kotlin to work as a developer in Japan, what type of companies use the language, and most importantly, how much you can earn as a Kotlin developer here.

Without further delay, let’s explore Kotlin in Japan.

The Popularity of Kotlin Programming Language in Japan

In its 12-year lifespan so far, Kotlin has become quite the powerhouse both in Japan and internationally, especially for the Android community. 

Here at Japan Dev, our team has personally vetted countless local and global companies operating in Japan. Thanks to the multitude of job listings we have received over the years from these companies, we’ve collected quite a bit of data.

This data has allowed us to see which programming languages appear the most frequently in our job listings. All we had to do was rank them according to the amount of job opportunities available for specific languages. 

This means that our popularity list directly reflects the IT job markets in Japan, and according to our data, Kotlin is the 7th most popular programming language in the country

Here’s our full list so you can see how Kotlin ranks against other popular languages:

Popularity Rank

Programming Language

Median Salary



¥9.8 million



¥8.6 million



¥10.3 million



¥8.6 million



¥9.3 million



¥9 million



¥9.1 million



¥9.2 million



¥8.7 million



¥8.7 million



¥9 million



¥8.5 million



¥10.1 million



¥10.86 million



¥8.7 million



¥7.2 million



¥8.5 million

As you can tell, 7th place is a pretty good ranking, especially considering that Kotlin is more popular than a language like Ruby, which gets more use in Japan compared to global rankings.

Another thing that caught our eye here is that Kotlin also seems to pay very handsomely in Japan. Let’s look into it.

How Much Do Kotlin Developers Earn in Japan?


Compared to other languages on our list, Kotlin salaries seem to be on the higher end of the IT salary scale in Japan.

The data we’ve collected from job listings has also allowed us to see how each programming language pays on average, and according to our data, Kotlin programmers earn an annual median salary of ¥9.1 million.

This is a significant difference between the median annual salaries of some of the higher-ranking programming languages like Java and JavaScript, both of which are in the 8-million range.

If you’d like to learn more about developer salaries in the country, head over to my developer salaries guide after this post.

As it pays this well, you may be wondering what type of jobs Kotlin is used for, so let’s look at this next.

How Is Kotlin Used in Japan: The Use Cases of Kotlin

It’s hard to pinpoint exactly what type of companies use Kotlin the most frequently. This is, essentially, a good thing

Seeing that Kotlin is used by startups as much as some of the larger, well-established companies in the industry proves that the use of Kotlin is widespread, appealing to all sorts of businesses at all levels.

That said, one thing is certain: Kotlin is most commonly used by companies with products that include Android applications. In fact, Android app development is, perhaps, the biggest use case of Kotlin in Japan.

In addition to developing Android apps, another common use case of Kotlin in Japan is supporting backend development. This wasn’t always the case, but things are evolving. 

In recent years, we’ve seen Kotlin used more and more as a server-side language. Companies nowadays commonly use Kotlin to support backend development for web and mobile applications.


Top Companies Using Kotlin in Japan

Kotlin is fairly popular in Japan, and it’s not hard to find some very solid examples of companies that use it here. We have a few notable ones on the Japan Dev job company list, so here are five companies in Japan that use Kotlin in their daily operations:

  • Money Forward: A noteworthy FinTech startup, Money Forward provides finance management tools to individuals and businesses. The company uses Kotlin in their day-to-day operations.

  • Mercari: The biggest success story from Japan’s startup scene, Mercari is Japan’s first unicorn startup, as well as the biggest second-hand marketplace app in the country. They use Kotlin to maintain their shopping and payment platforms.

  • Cybozu: Cybozu offers one of the best cloud-based collaboration platforms out there. The teamwork-focused company is a known subscriber of Kotlin.

  • Ubie: Created as a collaboration between a doctor and an engineer, Ubie is a med-tech startup that provides diagnosis software. The company uses Kotlin to provide its cutting-edge, AI-powered medical assistance app.

  • Sansan: Spearheading digital transformation in Japan, Sansan offers business-to-business services like a business card app and an invoice management system. The company is also among the ones that hire Kotlin developers.

Many more companies are offering Kotlin jobs in Japan, so let’s see how you can find them.

Finding Kotlin Jobs: Tips To Get Started

I recommend starting right here on the Japan Dev Kotlin jobs page. 

We manually select each company we feature on our job board, which is why these companies are all confirmed to have the best practices. 

So, if you’re new to Japan’s employment landscape and don’t want to end up working for a black company, we suggest picking up companies from our listing pool, which we review and update regularly.

Another thing you can do is join the Kotlin community in Japan and attend tech conferences and meetups. This is a great way to familiarize yourself with the tech scene in Japan, and find out what Kotlin specific skills you’ll need to hone. To learn more, check out my guides for Tokyo, Osaka, Kyoto, and Fukuoka communities.

Lastly, you can also contribute to open source projects or build one yourself to show off your skills and your drive to learn. This will not only significantly improve your resume but also put your name on the map as an active component of the Kotlin development community in Japan.

Concluding Words on Kotlin in Japan


As you can see, Kotlin is among the most popular programming languages on our job board. In fact, it’s among the top 10 languages in Japan today, and it also seems to pay on the better side of the scale. So, to go over some of the main points I covered:

  • Currently, Kotlin is the 7th most popular programming language in Japan

  • The language is most commonly used in Android development but is becoming popular as a backend support language

  • The annual median salary for a Kotlin developer in Japan is ¥9.1M, according to our data

So, if you’ve been wondering if learning Kotlin is worth your while, let me tell you that it absolutely is. Those proficient in Kotlin should have a generally easier time looking for Kotlin jobs in Japan as well.

That said, if you’re planning to learn Kotlin and get a job right away, I recommend checking out my top coding bootcamps guide to fast-track your learning process.


Japan Dev Team

This post was written by our Japan Dev editorial team.