Messaging Backend Engineer・Distributed Systems / LINE Platform

Job Summary

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.

This role focuses on backend development for LINE Messaging with a strong emphasis on distributed systems and storage technologies. You will work deeply with distributed data infrastructure such as Redis, Apache HBase, and next-generation distributed databases (such as YugabyteDB), ensuring high performance, consistency, and fault tolerance at scale.

You'll collaborate with engineers across multiple teams to solve challenging problems at scale, particularly around high-performance data-intensive workloads and large-scale distributed databases.

This is a role where your contributions will directly influence the quality and experience of messaging used by hundreds of millions globally. You will be expected to take initiative, drive improvements, and help shape the future architecture of our distributed storage systems, while adhering to best practices in software engineering and system reliability.

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.

This role focuses on backend development for LINE Messaging with a strong emphasis on distributed systems and storage technologies. You will work deeply with distributed data infrastructure such as Redis, Apache HBase, and next-generation distributed databases (such as YugabyteDB), ensuring high performance, consistency, and fault tolerance at scale.

You'll collaborate with engineers across multiple teams to solve challenging problems at scale, particularly around high-performance data-intensive workloads and large-scale distributed databases.

This is a role where your contributions will directly influence the quality and experience of messaging used by hundreds of millions globally. You will be expected to take initiative, drive improvements, and help shape the future architecture of our distributed storage systems, while adhering to best practices in software engineering and system reliability.

Mission & Goals

• Deliver a secure, high-performance, and scalable backend messaging platform that serves as critical infrastructure for global communication.
• Drive the evolution of system architecture through continuous technical innovation, focusing on the adoption, management, and optimization of distributed storage systems (e.g., Redis, HBase, YugabyteDB) and multi-data center architectures.
• Enhance system reliability and data integrity through thoughtful design of distributed architectures and long-term platform vision.
• Bridge the gap between application development and deep-tier middleware to support increasing user scale and diverse messaging use cases.

Responsibilities

• Design and implement server-side features, robust data structures for large-scale data storage, with a sharp focus on distributed processing, fault tolerance, and scalability.
• Optimize distributed database usage and develop storage-critical features for messaging and related services.
• Collaborate with cross-functional teams (including SRE and other backend teams) to improve data consistency, reliability, scalability, and observability across backend services.
• Contribute to long-term architecture and platform evolution strategies and next-generation distributed storages to ensure our systems can flexibly meet evolving business demands (e.g., Multi Datacenter Active-Active architectures, NewSQL databases integration, etc...).
• 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.

Mission/Goals

• Develop and support storage critical features for messaging and related services.
• Provide a reliable, flexible, scalable and secure storage solution for the platform adopting best practices.
• Research and integrate the next storage generation for the future of the platform such as Distributed SQL like TiDB and YugabyteDB.

 

Responsibilities

• Develop and maintain backend services for a high-scale and traffic intensive Messaging Platform.
• Design and optimize solutions over distributed databases.
• Ensure high availability, consistency, and disaster recovery strategies.
• Monitor and troubleshoot distributed database performance issues.
• Collaborate with cross-functional teams to improve system architecture.
• Maintain and improve observability to support the prevention, early detection, and root cause analysis of system outages.
• Promote automation and efficiency of the above distributed storage middleware operations deployment and management through tools and container orchestration.
• Research and integrate the next storage generation for the future of the platform such as Distributed SQL like TiDB and YugabyteDB.

Learn About the Product

• LINE Messaging , Social Graph and their related services.
  • https://www.line.me/en/
• LYP Premium.
  • https://premium.yahoo.co.jp/entry/order/top
• LY Federation Platform for ID federation with Yahoo and other groups' ID.

Ideal Candidate

• Interested in the challenging problems of complex, large-scale distributed systems and their solutions.
• Demonstrates strong critical thinking and problem-solving skills in high-concurrency environments.
• Takes initiative to solve problems, involves others, and takes ownership of the end-to-end lifecycle of a feature.
• Excel in positive communication, fostering strong relationships within diverse, international teams.
• Eager to learn new technologies (such as Distributed Databases) and grow as a specialist in distributed systems.

Required Skills ＆ Experience

• CS Fundamentals: Solid understanding of computer science fundamentals such as algorithms, data structures, networking, and concurrency.
• Experience: 3+ years of hands-on experience in server-side development.
• Teamwork: Proven experience working effectively within a software development team.
• Distributed Systems Interest: Strong interest in distributed storage middleware and ability to reason about problems in highly concurrent and distributed architectures (we are using Apache HBase, Redis, YugabyteDB, but no prior experience in this specific technologies is required).
• Language: Communication ability in written English for technical and cross-functional communication (no business level needed).
• Communication ability in spoken English or Japanese (daily conversation).

Preferred Skills ＆ Experience

• Experience in designing and developing server applications and databases that handle large amounts of data and large-scale traffic.
• Experience with distributed data systems such as Redis, Apache HBase, YugabyteDB, or similar technologies.
• Knowledge in consistency models, replication, partitioning, and distributed system trade-offs.
• Experience with SRE practices, including system reliability, incident management, production readiness, and defining and maintaining SLIs/SLOs.
• Experience with observability tools (e.g., Prometheus, Grafana, Elasticsearch, Kibana).
• Familiarity with security and privacy best practices.
• Hands-on experience with CI/CD pipelines and modern software development workflows.
• Familiarity with containerization technologies like Docker and Kubernetes.
• Conversational ability in Japanese is a plus (or a strong motivation to learn Japanese).

• Product & Service Development: Java, Kotlin, Scala, Spring Framework.
• Observability: Prometheus, Grafana, AlertManager, Elasticsearch, Kibana, Zipkin.
• Storage (RDBMS, NoSQL, NewSQL, Event Store): Redis, Apache HBase, Apache Kafka, YugabyteDB.
• 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 1,010,000
(Breakdown of standard salary)
　―Base salary: JPY 414,000 to JPY 778,000
　―Fixed overtime allowance: JPY 119,000 to JPY 223,000

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 Assessment

• Pre-interview technical assessment (including code review and system design, up to 120 minutes)
• Live coding interview
• Whiteboard discussion interview

Soft Skills & Cultural Fit

• Interview with team members, including discussions based on your resume

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.

Other

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.

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)

Work Location

Akasaka Office (Akasaka Trust Tower, 2-17-22 Akasaka, Minato-ku, Tokyo)

*The office at which you work upon hire will be your assigned location. Thereafter, there is a possibility of reassignment to all business locations as 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.
Note: 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

Benefits

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, LY Corporation Working Style allowance, in-house massage room, club activities, subsidy for employee social events, and more