Senior Frontend Engineer - EC Expansion Development Department (ECEXD)

Location: Tokyo, Japan

Time Type: Full time

Job Description

Job Description:

Department Overview

The EC Expansion Development Department is guided by a mindset of building a lean and efficient organization, and delivers products and systems that continuously strengthen and expand e-commerce. In a fast-changing business environment, we actively leverage AI and other advanced technologies to deliver value at speed, growing as a team through ongoing challenges and continuous improvement.
 

Among these, the Marketplace Expansion Development Section develops and operates services such as the J.League Online Store, Furusato Nozei (Hometown Tax), Rakken, and Raxy. Additionally, the team is responsible for launching new EC-related services with the goal of expanding and growing Rakuten's marketplace. This is a highly challenging department where you can gain unique and valuable experiences that are distinct to Rakuten.
 

Position:

Why We Hire

We are seeking an experienced Senior Frontend Engineer who combines strong technical expertise with exceptional cross-functional communication skills and leadership experience. This role requires someone who can bridge the gap between engineering, product, design, and business stakeholders while contributing to frontend development initiatives from early planning stages through implementation and deployment.

Our development team is a global hybrid, with members based at HQ in Japan and in China. We are responsible for multiple systems, including the storefront, order management, and inventory management, with teams dedicated to each area.

This position will be responsible for technical decision-making, coordinating with various stakeholders, and ensuring the delivery of high-quality frontend solutions. This position requires strong business-level Japanese communication skills to effectively collaborate with internal stakeholders and partner departments. Prior experience managing a team or leading projects is highly valued.

Position Details

Primary Responsibilities

- Participate in frontend development projects from early planning and requirement definition through implementation and deployment

- Coordinate with product managers, designers, backend engineers, and business stakeholders in Japanese to define requirements and project scope

- Design and implement end-to-end frontend systems with a focus on quality, performance, and maintainability

- Write technical specifications and design documents following team guidelines

- Build reusable, accessible, and performant React components

- Conduct code reviews and mentor team members when needed

- Present technical proposals and progress reports to both technical and non-technical stakeholders

- Take ownership of complex features and drive technical initiatives that improve team productivity

What Makes This Role Unique

- Leadership Opportunity: Opportunity to lead technical initiatives and mentor team members

- Business Impact: Direct influence on product direction through stakeholder engagement

- Modern Tech Stack: Next.js 15 (App Router), React 19, TypeScript, TanStack Query, Zustand, shadcn/ui, Tailwind CSS

- Production Scale: High-traffic e-commerce platform serving millions of users

- End-to-End Ownership: Involvement from early requirement gathering and technical planning to production deployment

- Cross-Cultural Environment: Work with global teams across Japan and China

- AI-Powered Development: Access to cutting-edge AI tools including Claude Code, GitHub Copilot, and other AI assistants to accelerate development

Work Environment

Frontend Engineer Team members

- 7-9 members

Mandatory Qualifications:

Experience & Leadership

- 5+ years of professional frontend development experience

- 3+ years of people management experience in a team (approx. 3 members)

- Experience in successfully delivering frontend projects from early-stage project processes (requirements gathering, technical planning, and system design) to deployment

- Experience coordinating with cross-functional teams (product, design, backend, QA)

Language & Communication

- Japanese & English: Business level or higher

Core Technical Stack

- React expertise (required): Deep understanding of component lifecycle, Hooks, and modern patterns (React 16+)

- TypeScript: Strong proficiency with generics, utility types, and type-safe patterns

- Next.js: Hands-on experience with App Router or Pages Router

- Modern JavaScript (ES6+), HTML5, CSS3, responsive design

- Modern CSS approaches: Tailwind CSS, CSS Modules, or CSS-in-JS

- Testing: Unit, integration, and E2E testing (Jest, React Testing Library, Playwright)

- Git workflows and code review practices

Desired Qualifications:

Leadership & Project Management

- Experience with agile/scrum methodologies and sprint planning

- Experience as a technical point of contact for stakeholder communication

- Experience writing technical specifications, RFCs, or design documents

- Familiarity with project management tools (Jira, Asana, Linear, Notion)

- Experience working directly with product managers to define roadmaps

- Understanding of e-commerce business models and metrics

Technical Experience

- Production experience with our tech stack (Next.js App Router, React 19, TanStack Query, Zustand)

- Experience with e-commerce or high-traffic consumer applications

- Experience with server-side React patterns: RSC, Streaming SSR, Suspense

- Experience with design systems and component library development

- Understanding of web accessibility (WCAG) and Core Web Vitals optimization

- Familiarity with error monitoring tools (Sentry, Datadog, Cloud Logging)

- Experience with internationalization (i18n) libraries and strategies

- Familiarity with Figma or other design tools for design collaboration

- Understanding of SEO best practices

- Experience using AI coding assistants and reviewing AI-generated code for correctness, security, and best practices

Other Information:

Additional information on Location

Rakuten Crimson House (Head office)

Additional information on English Qualification

TOEIC Score exceeding 800 (or similar level of English ability) or a University Degree earned in an English-speaking country.

Proof of qualifications will be required by the time of the job offer.

If no evidence is available to prove the qualifications denoted above, taking an IP test, organized by Rakuten, during selection process is required.

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