Messaging Senior / Staff Backend Engineer / Messaging Platform

Position Outline

We are seeking an experienced Backend Software Engineer to join the team powering a large-scale messaging platform. This role involves designing, implementing, and evolving critical backend systems that enable real-time communication for hundreds of millions of users globally. You will play a key technical leadership role, driving reliability, performance, and security, and contributing to system architecture and engineering standards across teams.

As a senior member of the team, you will be responsible for highly scalable and reliable backend services handling tens of billions of messages per day. Your work will focus on long-term architectural initiatives, cross-functional collaborations, and continuous improvements in scalability and maintainability.

You will provide technical leadership in developing new features, system optimization, fault tolerance, observability, automation (CI/CD), and mentorship for other engineers. You will help define engineering standards and influence platform strategy aligned with future business needs.

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Mission and Goals

• Deliver a secure, high-performance, scalable backend messaging platform as global communication infrastructure.
• Continuously evolve the architecture to support growing user bases, new features, and diverse use cases.
• Enhance reliability, maintainability, and observability via robust design and long-term technical vision.

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Responsibilities

• Lead design/implementation of scalable backend features and APIs for the messaging platform.
• Architect distributed systems focusing on scalability, fault tolerance, and adaptability to platform demands.
• Collaborate cross-functionally with Product, SRE, Security, and other Platform teams to boost system reliability, observability, and user experience.
• Drive test automation, monitoring, and incident response practices.
• Shape technical vision and roadmap for backend architecture to meet future needs.
• Mentor engineers, foster a culture of quality, and promote continuous improvement.
• Establish and refine best practices and technical standards.
• Stay updated on industry trends to inspire ongoing innovation.
• On-call support may be required for 24/365 service availability.

Note: Responsibilities may change based on company needs.

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Ideal Candidate

• Passionate about building complex, large-scale distributed systems.
• Exhibits strong analytical, logical, and critical thinking skills.
• Actively identifies and resolves technical challenges.
• Effective collaborator and communicator across teams and audiences.
• Supports team success through mentoring and sharing knowledge.
• Balances technical ambition with practical execution aligned to team goals.

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Required Skills & Experience

• Significant experience architecting/contributing to distributed systems in high-traffic environments.
• Strong programming skills in Java, Kotlin, Scala, or similar for backend service development.
• Experience leading complex, high-impact projects with cross-functional coordination.
• Proven ability to drive technical direction and standards across teams.
• Skilled in system monitoring, incident management, and reliability.
• Demonstrated self-drive, timely delivery, and collaborative teamwork.
• Ability to mentor and improve practices team-wide.
• Fluent in written and spoken English (or Japanese) for technical communication.

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Preferred Skills & Experience

• Experience with distributed data stores (Redis, MongoDB, Apache HBase, Apache Kafka).
• Proficient in SRE practices (defining/monitoring SLIs/SLOs).
• Knowledge in backend security engineering.
• Test engineering for highly concurrent systems.
• Strong background in CI/CD pipelines and deployment.
• Experience with observability tools (Prometheus, Grafana, Elasticsearch, Kibana).
• Experience with Kubernetes and container orchestration in production.

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Development Environment

• Languages/Frameworks: Java, Kotlin, Scala, Spring Framework
• Observability: Prometheus, Grafana, AlertManager, Elasticsearch, Kibana, Zipkin
• Storage: Redis, Apache HBase, Apache Kafka, MongoDB
• Infrastructure: Kubernetes, private cloud platforms

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Compensation & Benefits

• Annual Salary: JPY 12,000,000 to JPY 20,000,000
  (Includes monthly salary with fixed overtime allowance)
• Standard Monthly Salary: From JPY 800,000 (negotiable)
  • Base salary: From JPY 621,000 (negotiable)
  • Fixed overtime allowance: From JPY 119,000 (negotiable)
  • Overtime allowance covers 35 hours; additional overtime is paid separately
• Bonuses: Up to twice per year, based on company/department performance
• Allowances: Overtime, commuting (up to JPY 150,000/month), remote work environment (JPY 11,000/month), etc.
• Employment Type: Permanent (with 3-month trial period)
• Work Location: Tokyo (wheelchair accessible; no indoor smoking except in designated rooms)

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Work Hours & Leave

• Flextime: Standard hours 7 hrs 45 mins/day; flexible start/end times
• Core Hours: None (typical hours: 9:30 AM–6:15 PM)
• Shortened hours: Available for childcare/caregiving
• Time Off:
  • 2 days/week (weekends), national holidays, New Year's (Dec 29–Jan 4)
  • Paid leave, special paid leave (condolence, maternity, sick, childcare, nursing, etc.), sabbatical leave, "Happy Friday"

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Benefits

• Comprehensive social insurance (health, nursing, pension, employment, worker's compensation)
• Optional defined contribution pension, group life/disability insurance
• Savings and stock programs
• Club activities, social event subsidies, in-house massage room
• Health exam re-exam subsidies

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Talent Development / Support

• Employee/management training, language courses
• Sabbatical leave, doctoral studies support

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Selection Process

1. Application
2. Coding Test / Assignment
3. Interviews & Background Check
4. Offer

• Document screening results will be notified within two weeks
• The interview process includes multiple rounds and can take 4–6 weeks from application
• No inquiries regarding the outcome or criteria of the selection process

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Additional Information

• Remote work support provided
• Offices are accessible and equipped with non-smoking areas
• Some roles may require shift work or standard office hours

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