iOS/Android Client Engineer / LINE app

TokyoLINE CorpEngineeringiOS, Android, Client-sideFull-time


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 native app development: High Performance CPU like M1 Max, 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. 

  1. Individual Contributor: As an individual engineer, you'll build on your technical skills and contribute to the team with your designs, codes, and reviews.
  2. Tech Lead: You will lead a small to medium-sized team of engineers in development and help them strengthen their technical skills.
  3. 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 pm(actual working hours 7 hr 30 min)
*To be determined after the interview process


Weekends (Saturdays and Sundays), national holidays, paid leave, New Year’s holiday, congratulatory and condolence leave, "Refreshment" leave (every 5 years, employees who have been employed under a continuous contract are entitled to 10 days of paid leave)


Annual salary system (To be determined based on skills, experiences and abilities after discussions)

  • Annual compensation will be divided into 12 months and paid on a monthly basis.
  • Separate incentives available (*1)
  • Compensation revision: twice a year
  • Allowances: commuting allowance, LINE Pay Card Benefit Plan (*2)
    (*1) In addition to your annual compensation, you may receive incentives (twice a year) depending on the company's and individual performance and evaluation on your performance. (Incentives are not guaranteed to be provided. An incentive payment will only be paid if you remain employed as of the payment date.
    (*2) This is an allowance separate from the salary meant for employees to use for their health, personal development, support for raising the next generation, and more.


  • Employment insurance, workers accident compensation insurance, health insurance, employees pension insurance


  • Periodic health checkup
  • Company events and others



*Implementation of second-hand smoke prevention measures

[Prohibiting Indoor Smoking (other than Smoking Room)]
Shinjukul, Osaki, Minami-shinjuku, Yotsuya
[Prohibiting Indoor Smoking (outdoor Smoking Area)]
Shinuku (NEX), Nishi-shinjuku



Details to be shared during interviews.

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