Backend Engineer / Distributed Database・Messaging Service / LINE Platform

Position Outline

We are looking for engineers to design, build, and maintain a large-scale, distributed backend for a Messaging Platform, with a focus on distributed database engineering under high data and traffic volumes.

Job Details

• Develop high-performance, data-intensive backend services.
• Optimize distributed database usage.
• Ensure system reliability.

The platform handles tens of billions of messages daily using thousands of servers and distributed storages (e.g., Redis, Apache HBase). The large scale presents unique, challenging problems.

Engineers will collaborate with backend engineers and SREs to:

• Develop new features.
• Enhance data consistency, scalability, and fault tolerance.

Example Tech Talks:

• Traffic intensive storages at Messaging Application
• Messaging Platform Data Pipeline & HBase/Kafka Utilization
• Scalable Multi-Data Center ID Generator

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

---

Mission/Goals

• Develop and support storage-critical features for messaging and related services.
• Provide reliable, flexible, scalable, and secure storage solutions adopting best practices.
• Research and integrate the next generation of storage, e.g., Distributed SQL (TiDB, YugabyteDB).

---

Responsibilities

• Develop and maintain backend services for large-scale, high-traffic Messaging Platform.
• Design and optimize solutions for distributed databases.
• Ensure high availability, consistency, and disaster recovery strategies.
• Monitor and troubleshoot distributed database performance.
• Collaborate with cross-functional teams to improve system architecture.
• Maintain and improve observability for outage prevention and root cause analysis.
• Promote automation of distributed storage middleware deployment and management.
• Research/integrate next-gen storage (e.g., TiDB, YugabyteDB).

Responsible Services

• Messaging, Social Graph, and related services.
• ID Federation Platform.
• Premium features.

---

Ideal Candidate

• Enthusiastic about solving complex, large-scale distributed systems challenges.
• Takes initiative, involves others, and is responsible.
• Values positive communication and cooperation across diverse teams.
• Eager to learn new technologies and find practical solutions.

---

Required Experience/Skills

• Degree in Computer Science (or related), or equivalent work experience.
• Experience in development/operation in Linux/Unix environments.
• Ability to resolve problems in highly concurrent and distributed architectures.
• Strong interest in distributed storage middleware (e.g., HBase, Redis).
• Independent problem-solving attitude.
• Communicates in spoken Japanese and written English.

---

Preferred Experience/Skills

• Developed/operated distributed systems handling large data and traffic.
• Experience with concurrent/multithreaded system development.
• Experience with internal database implementation (RDBMS, KV stores).
• Proficiency in JVM-based languages (Java, Kotlin).
• SRE practices: observability, SLOs, error budgets, infrastructure as code, release engineering.
• Familiarity with observability tools (ELK Stack, Prometheus, Grafana, etc.).
• Experience with provisioning tools (Ansible) or container orchestration.
• Incident response experience.
• Motivated to learn Japanese and English.

---

Development Environment

• Storage: Redis, Apache HBase, Apache Kafka.
• Development: Java, Kotlin, Spring Framework.
• Observability: Prometheus, Grafana, AlertManager, Elasticsearch, Kibana, Zipkin.
• Infrastructure: Kubernetes, Private VMs/Cloud.
• CI/CD/Automation: Ansible, ArgoCD, Jenkins, GitHub Actions.

---

Salary

• Annual Salary: JPY 7,000,000 – JPY 18,000,000
• Monthly Salary: JPY 467,000 – JPY 1,200,000
  • Base: JPY 361,000–934,000
  • Fixed overtime (35 hours): JPY 105,000–267,000
  • Overtime beyond 35 hours paid separately
• Bonuses: Up to 2/year, based on performance

---

Employment Details

• Type: Permanent (no fixed period)
• Work Location: Kioicho, Chiyoda-ku, Tokyo
  • Wheelchair accessible
  • No smoking indoors in principle (smoking rooms available)
• Work Hours: Flextime (standard 7h 45m, no core hours)
  • Typical: 9:30 a.m. – 6:15 p.m. (may vary by department)
• Remote Work Allowance: JPY 11,000/month

---

Holidays and Leave

• Days Off: 2/week (Sat & Sun), national holidays, New Year (Dec 29–Jan 4)
• Leave: Paid leave, special leave (condolence, maternity, sick/childcare, etc.), Happy Friday, sabbatical
• Flexibility: Special arrangements for employees with childcare/nursing responsibilities

---

Benefits

• Defined Contribution Pension Plan (optional)
• Group welfare insurance, long-term disability insurance
• Employee savings and stock investment programs
• Re-examination subsidy after health checks
• Working Style allowance
• In-house massage, club activities, employee event subsidies, and more

---

Allowances

• Overtime allowance
• Commuting allowance (per days at office, up to JPY 150,000/month)
• Remote work allowance

---

Selection Process

1. Coding test/assignment
2. Interviews (including web coding and whiteboard/discussion)
3. Background check
4. Offer

Technical and cultural fit emphasized throughout the process.

---

Hard Skills Evaluation

• Pre-interview web coding test (up to 3 hours)
• Live coding interview
• Whiteboard discussion

Soft Skills Evaluation & Cultural Fit

• Interviews with team, resume-based discussions

---

Notes

• Personal information required for recruitment purposes only.
• Resume and other documents will not be returned.

---

Related Roles

• Backend Engineer (DBaaS for OpenSearch) / Private Cloud
• Cloud Platform Engineer (Kubernetes) / Private Cloud
• Security Engineer (Application Security)

---

This job description omits proprietary company-related detail and application form. For more information or to apply, refer to the standard recruitment channels.