iOS/Android Client Engineer / LINE app

  • Tokyo
  • Remote OK
  • Full-time
  • December 6, 2022
Apply from Japan Only
(You must live in Japan to apply)
Language Requirements
Japanese: Conversational
English: Business Level
Minimum Experience
Mid-level or above

Our Mission

Our team works on features and under the hood improvements for the Android and iOS clients of the LINE messaging app, doing our part to make LINE Corp's mission of "Closing the Distance" into a reality.
The app's place in users' daily lives means we go beyond simply developing new features: we strive to provide a stable application by constantly working on improvements. 

About the Team

In addition to LINE's other domestic offices, our team collaborates with colleagues in South Korea, Taiwan, Vietnam, and other overseas offices.
With our members hailing from over 15 different countries, our Japan team itself is also cosmopolitan. 
We mainly use English for documentation and chats, and also communicate verbally in English at times. 
We use GitHub's Pull Requests to review each other's code and hold study sessions. 

Team members actively contribute to OSS and are encouraged to attend and/or present at external conferences and workshops. 
Some of our members' recent achievements include contributions to Swift, OSS for iOS and Android, and presenting at DroidKaigi, iOSDC, and AltConf.


Leverage your expertise to develop and improve LINE's Android and iOS clients. 
Collaborate with planners, UI/UX designers, data scientists, business development teams, and other stakeholders. 

Who You Are

  • You take initiative and go beyond your current role to boost team productivity through codebases, improving tools, and helping team members expand their knowledge.
  • You endeavor to contribute quality output by proposing improvements for plans, development specifications, and tests. 

Current Product Phase/Exciting Challenges/Opportunities

You'll be involved in the development of the LINE client app, which is used by hundreds of millions of people in Japan and abroad (particularly in Asia). This means you'll have the opportunity to be a part of the planning and development of an app that is popular both domestically and globally. 
Additionally, our codebase has grown massively in size since the LINE app was launched eight years ago. You'll work on improving the codebase's internal structure as well as the performance and UX of the app itself. 
Through code reviews that let developers learn and improve from one another, automated CI testing, and other workflows we’ve created, we ensure all the development work we do is sustainable. 

Tools/Development Environment

Devices used in development: 
MacBook Pro, iMac 5K, etc. (recommended configuration for development: Core i9 or better, over 32GB memory, over 1TB SSD)
More than one device can be loaned upon request. Developers are also provided with extra monitors and standing desks. 

Github Enterprise, JIRA, Confluence, LINE, Slack, Jenkins
Use Thrift IDL to collaborate with other teams
Android: Java + Kotlin (mixed project), Gradle, Kotlin coroutine, RxJava2, Feature Flag systems, etc. 
iOS: Swift + Objective-C (mixed project), Fastlane, XcodeGen, Bazel, etc. 

Career Path

We have a leveling system that assigns you a "career level" based on performance expectations.

You can choose from three career paths after joining. 

l  Individual Contributor: As an individual engineer, you'll build on your technical skills and contribute to the team with your designs, codes, and reviews.

l  Tech Lead: You will lead a small to medium-sized team of engineers in development and help them strengthen their technical skills.

l  Engineering Manager: You will manage a medium to large-sized team of engineers and endeavor to maximize the team's output.

You’ll also have the opportunity to move teams when internal job postings open up once a year.

You can take translation support into English or Korean when you communicate with the people in other department of business teams. However, please make sure that Japanese skill of business level is required sometime.


  • Japanese or English skills in addition to experience in one of the following
  • 3+ years of experience using Swift/Objective-C to develop native iOS apps
  • 3+ years of experience using Kotlin/Java to develop native Android apps

Preferred Qualifications

  •  Basic computer science knowledge (algorithms, data structures, asynchronous I/O, databases, networks, etc.)
  • Knowledge of and experience with UI/UX design and development (custom views, interaction, etc.)
  • Knowledge of and experience with standard libraries, frameworks, and build tools
  • Knowledge of and development experience with hybrid applications (web/native)
  • Active contribution and participation in open source software and developer communities
  • Interest or previous experience in messaging services

Working Hours

One of the followings will be applied: Discretionary labor system for professional work (Employee is deemed to have worked for 9.5 hours a day, regardless of the actual number of hours worked), Flex-time system (core time: 11:00 am–4:00 pm) or 10:00 am–6:30 pmactual working hours 7 hr 30 min)
*To be determined after the interview process



LINE is the most popular communication app in Japan, Thailand and Taiwan. The diverse platform is continuing to grow rapidly throughout Asia, expanding services around the globe.

Under its corporate mission of "Closing the Distance," we strive to bring people around the world closer to each other, to information, and to services.

Our vision is to become the “life infrastructure” for its users, always ready to fulfill their needs, 24 hours a day, 365 days a year.

With mobile-focused projects in a wide variety of areas including communication, contents, entertainment and others, LINE is expanding into projects related to development, operations, advertising, Fintech, AI, Blockchain and more.


LINE is a global development team with development centers in more than seven countries. Based on the messenger service, we develop and operate various services such as fintech, news, games, and music services.


LINE is a service with more than 185 million MAUs and handles traffic for a variety of services based on this user in real time.


LINE has the ability of the best engineers in each field to develop the best services. It creates individual growth in a global engineering culture.

LINE's policies during COVID-19 are as follows

We’ve introduced a number of initiatives to support our users in Japan and around the world:

  • Remote consultations with medical professionals and one-on-one counseling for those suffering from anxiety and stress stemming from COVID-19 (working w/ Japan’s Ministry of Health, Labour and Welfare)
  • Enabling most of the employees to work from home
  • Moving to conducting recruitment interviews over video chat
  • Shifting all contracts to electronic form to allow those who handle contracts to work from the safety of their homes

    You can find more details about our initiatives in response to the spread of novel coronavirus here
View LINE's company page

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