Messaging Backend Engineer / LINE Platform

Position Outline

As a core member of the Messaging Platform team, you will be responsible for designing, implementing, and operating scalable and reliable backend services that process tens of billions of messages per day across the LINE ecosystem.
Your work will focus on maintaining and developing new features considering the performance, security, and evolution of critical infrastructure powering real-time messaging.

You'll collaborate with engineers across multiple teams to solve challenging problems at scale delivering robust solutions.
This is a role where your contributions will directly influence the quality and experience of messaging used by millions globally. You will be expected to take initiative, drive improvements, and help shape the future architecture of our systems, while adhering to best practices in software engineering, CI/CD, and system reliability.

Organization's Mission and Goals

  • Deliver a secure, high-performance, and scalable backend messaging platform that serves as critical infrastructure for global communication.
  • Evolve the architecture through continuous technical innovation to support increasing user scale, new features, and diverse messaging use cases.
  • Enhance system reliability, maintainability, and observability through thoughtful design, robust data structures, and long-term platform vision.

Responsibilities

  • Design and implement server-side features and internal APIs that support LINE's core messaging platform.
  • Design and implement robust data structures for large-scale data storage, with a sharp focus on distributed processing, fault tolerance and scalability.
  • Collaborate with cross-functional teams to improve reliability, scalability, and observability across backend services.
  • Contribute to long-term architecture and platform evolution strategies to ensure our systems can flexibly meet evolving business demands.
  • Drive initiatives to improve CI/CD workflows, testing coverage, and system monitoring.
  • Depending on the team and specific components, this role may include on-call responsibilities to support our 24/365 service availability.

*Scope of Change: There is a possibility of reassignment to any duties as determined by the company.

Learn About the Product

  • LINE
    • This is a communication app that allows you to seamlessly connect with people, information, services, companies and brands, including talk, voice calls, and video calls where you can enjoy conversation.
  • LYP Premium
    • This is a monthly membership service that allows you to use services and benefits exclusively for LYP Premium members designated by LY Corporation.
  • Related services

Learn About the Organization and People

LINE Platform Server Function 開発チーム参考情報一覧

Our team is composed of talented engineers from diverse countries and backgrounds. We foster a culture of curiosity, learning, innovation, mutual trust and proactivity that empowers us to deliver at scale and adapt quickly to change.

Ideal Candidate

  • Interested in the challenging problems of complex, large-scale distributed systems and their solutions.
  • Demonstrates strong critical thinking and problem-solving skills.
  • Takes initiative to solve problems, involves others, and takes ownership.
  • Excel in positive communication, fostering strong relationships within diverse, international teams.
  • Eager to learn new technologies and grow as an engineer.
  • Able find realistic solutions according to the team's situation and schedule, and execute tasks efficiently.

Required Skills & Experience

  • Solid understanding of computer science fundamentals such as algorithms, data structures, networking, and concurrency.
  • 3+ years of hands-on experience in server-side development.
  • Experience working in a development team.
  • Fluent in either Japanese or English (written and spoken) for technical and cross-functional communication.

Preferred Skills & Experience

  • Experience in designing and developing server applications and databases in high-traffic environments.
  • Knowledge in Security and Privacy Engineering within distributed systems.
  • Experience using and integrating distributed databases (e.g., Redis, MongoDB, Apache HBase, Apache Kafka).
  • Experience with SRE practices, including system reliability, incident management, production readiness and defining and maintaining SLIs/SLOs.
  • Experience in Test Engineering, especially for large-scale backend systems.
  • Experience with observability tools (e.g., Prometheus, Grafana, Elasticsearch, Kibana).
  • Hands-on experience with CI/CD pipelines and modern software development workflows.
  • Familiarity with containerization technologies like Docker and Kubernetes.
  • Familiarity with security best practices.

Development Environment

  • Product & Service Development: Java, Kotlin, Scala, Spring Framework.
  • Observability: Prometheus, Grafana, AlertManager, Elasticsearch, Kibana, Zipkin.
  • Storage (RDBMS, NoSQL, Event Store): Redis, Apache HBase, Apache Kafka, MongoDB.
  • Infrastructure: Container (k8s), private cloud (Flava/Verda).

Salary

Expected annual salary: JPY 8,000,000 to JPY 15,000,000
Form of salary: Monthly salary (including fixed overtime allowance)
Standard monthly salary: JPY 534,000 to JPY 1,001,000
(Breakdown of standard salary)
 ―Base salary: JPY 414,000 to JPY 778,000
 ―Fixed overtime allowance: JPY 119,000 to JPY 223,000

Fixed overtime allowance of 35 hours will be provided, regardless of whether overtime work is performed.
 Note 1: Overtime allowance is paid separately for overtime work in excess of the fixed 35 hours.
 Note 2: Names of items related to monthly salary vary depending on the grades.
 Bonuses are granted a maximum of two times a year. The amount is determined by factors including the company's and your department's performance.

Allowances

Overtime allowance, commuting allowance,*1 LY Corporation Working Style allowance,*2 etc.

*1 You will be paid for the number of days you actually came to the office. (Maximum of JPY150,000/month)
*2 Allowance to improve your remote work environment (JPY11,000/month)

Type and Period of Employment

Type of employment: permanent employee (no fixed period of employment, 3-month trial period)

*No fixed period of employment

Work Location

Kioicho Office (Kioi Tower, 1-3 Kioicho, Chiyoda-ku, Tokyo)

*You may be required to report to your assigned office based on work instructions. Initially, the office you report to will be your assigned location. Afterward, there is a possibility of reassignment to any business location determined by the company.
*The offices are wheelchair accessible.
*Note on measures against passive smoking: In principle, no smoking indoors (smoking rooms are available).

Work Hours

  • Flextime system: standard work hours 7 hours 45 minutes (no core hours)
    • Start and end times are up to the individual. However, the company's standard working hours are from 9:30 a.m. to 6:15 p.m.
  • Shortened working hours system available for childcare and caregiving.

*Some departments may operate on the standard work hours (9:30 a.m. - 6:15 p.m.), while others may have a shift schedule.

Holidays and Leave

  • Days Off: Two days off per week (Saturdays and Sundays*1), national holidays, New Year's holiday (December 29 to January 4)

  • Leave: Paid leave, special paid leave (for condolence, maternity, sick childcare, nursing care, legally-designated communicable disease, etc.), Happy Friday*2, sabbatical leave

*1 May differ depending on department.
*2 When a public holiday falls on a Saturday, employees will be given the previous business day off.

Benefits

Comprehensive social insurance (health insurance, nursing care insurance, welfare pension insurance, employment insurance, workers' compensation insurance), Optional Defined Contribution (DC) Pension Plan, Comprehensive Welfare Group Term Insurance, Group Long-term Disability, Employee Savings Program, Cumulative Stock Investment Program, subsidy for re-examination after regular basic/comprehensive health checkup, in-house massage room, club activities, subsidy for employee social events, and more

Talent Development/Support Systems

Training for Employees, Language Courses, Management Training, LY Corporation Job Challenge, Sabbatical Leave, Doctoral Studies Support Program, and more

Selection Process

  • Step1

    Application

  • Step2

    Coding test/Assignment

  • Step3

    Interviews/ Background Check

  • Step4

    Offer

We have designed our selection process with an emphasis on technical aptitude and shared values.Through this process, we aim not only to assess technical skills but also to deepen mutual understanding with the team.

Hard Skills Evaluation

  • Pre-interview Web Coding Test (up to 3 hours)
  • Live Coding interview
  • Whiteboard Discussion interview

Soft Skills Evaluation & Cultural Fit

Interviews with team members, discussions based on the resume

How to Apply

Please fill out and submit the application form. To assess your eligibility for the position, we kindly ask you to provide the necessary personal information on the application form. Please note that this information will only be used for recruitment purposes. Please also note that your resume or other submitted documents will not be returned.

Document Screening

You will be notified of the results of the selection process within two weeks at the e-mail address you entered in the application form, regardless of whether your application is accepted or not. It may take about one week longer if the application period falls during the Golden Week and the New Year holidays.

Interview, aptitude test, technical test, compliance check/reference check

Applicants who pass the document screening will be required to undergo multiple interviews, aptitude/technical tests, compliance checks, and reference checks, although the details vary depending on the position.

You will be notified of the results of the selection process within two weeks at the e-mail address you entered in the application form, regardless of whether your application is accepted or not.

The schedule will vary depending on interviews and other factors, but if everything goes smoothly, an internal offer will be made within about four to six weeks after the application is submitted. Please note that we will not respond to inquiries regarding the details or criteria of the selection process or the reasons for the results, regardless of the results of your application.

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