Senior Frontend Engineer, BSS Platform - BSS Development Department (BSDD)

Job Description:

Business Overview
The Technology Platforms Division (TPD) drives the growth of the Rakuten Ecosystem by delivering innovative, high-quality technology platforms characterized by integrated control and strategic partnerships.
Within TPD, the Telecom Business Application Supervisory Department (TBASD) develops and maintains a unified, high-quality Business Support System (BSS) for Rakuten Mobile. We deliver agile, scalable solutions across the customer lifecycle and continuously enhance system performance through close collaboration with stakeholders.

Department Overview
At BSS Development Department (BSDD), we are managing and evolving the Business Support Systems (BSS) platform, a critical backbone of Rakuten Mobile services. The main functions that BSS provides are: end-customer touchpoints (front-ends, mobile applications for onboarding and for plan management), billing and integration with the core systems of Rakuten Mobile.
Just as Rakuten Mobile has disrupted the mobile industry, we're committed to delivering exceptional value to our business partners and end customers by seamlessly leveraging the wide Rakuten Ecosystem. With a long history of software engineering as a service company providing social infrastructure, we value the speed and quality of our delivery to maximize customer satisfaction.
Our mission is to provide a unified BSS platform that spans across the different business lines of our telecommunication businesses. Having just finished the initial build-up phase of the platform, we are actively looking for talented individuals to make our organization and platforms stronger with teams spanning Japan, India, China, and Singapore.

Position:
Why We Hire
The department is responsible for the following core domains:
・Customer-facing frontend applications and mobile apps (onboarding, plan management, My Rakuten Mobile)
・Billing and charge management systems
・Order management and provisioning workflows
・Integration layers connecting BSS with Rakuten Mobile's core network and third-party systems 

With the BSS platform now entering a sustained growth and optimization phase, we are expanding our team of engineers who can take deep technical ownership of customer-facing frontend applications. As user expectations and UI complexity grow, we need Senior Frontend Engineers who can independently drive the design and delivery of sophisticated frontend features, elevate interface quality across the team, and serve as technical anchors in cross-functional squads.

This role is central to ensuring the usability, performance, and reliability of applications used by millions of Rakuten Mobile subscribers.

Position Details
・Design, develop, and maintain high-performance, production-grade frontend applications for BSS platform domains including subscriber self-service portals, onboarding flows, plan management, and internal operational tools
・Lead technical design (HLD/LLD) for new UI features and system enhancements, ensuring alignment with platform architecture and UX standards
・Conduct thorough code reviews and uphold engineering quality across the team
・Collaborate closely with product managers, UX/UI designers, QA engineers, backend engineers, and counterpart teams across global offices to deliver end-to-end features
・Diagnose and resolve complex frontend production issues, contributing to root cause analysis and long-term systemic fixes
・Mentor junior and mid-level engineers through design reviews, pair programming, and technical guidance
・Contribute to CI/CD pipeline improvements, frontend observability tooling, and DevOps best practices
・Participate in cross-team architecture discussions and help drive platform-level frontend technical decisions
・Champion accessibility, responsive design, and cross-browser compatibility standards across the team

Work Environment
・Global distributed team across Japan, India, China, and Singapore
・Agile/Scrum development with two-week sprint cycles
・English as the primary working language for documentation, design discussions, and cross-site communication
・Modern tech stack: React/TypeScript-based single-page applications, containerized on Kubernetes, deployed on cloud infrastructure
・Strong emphasis on engineering craftsmanship: code review culture, automated testing, and continuous delivery

Mandatory Qualifications:
・5+ years of frontend software development experience delivering large-scale production web applications
・Strong proficiency in React and TypeScript; deep understanding of component architecture, state management, and rendering performance
・Proven experience designing and consuming RESTful APIs and integrating with microservice backends
・Solid command of modern CSS (CSS Modules, styled-components, or equivalent) and responsive/accessible design principles
・Experience with frontend testing strategies: unit testing (Jest, Vitest), integration testing, and E2E testing (Playwright, Cypress, or equivalent)
・Hands-on experience with build tooling and CI/CD pipelines (Webpack, Vite, or equivalent; GitHub Actions or equivalent)
・Ability to independently lead technical design (HLD/LLD) and communicate design decisions to cross-functional stakeholders
・Business Level English (TOEIC 800 or above, or equivalent qualification)

Desired Qualifications:
・Experience in telecommunications, BSS/OSS systems, or related domains (billing portals, order tracking, CRM UIs, or provisioning dashboards)
・Familiarity with micro-frontend architecture and module federation
・Experience with server-side rendering or static site generation (Next.js or equivalent)
・Track record of mentoring engineers and driving frontend quality improvement initiatives within a team
・Exposure to frontend observability tooling (Datadog RUM, Sentry, or equivalent)
・Experience working with design systems and contributing to shared component libraries
・Familiarity with GraphQL or BFF (Backend for Frontend) patterns
・Experience in agile environments with globally distributed teams

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