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Senior Front-End Tech Lead - Build High-Traffic E‑Commerce UX
| Location | Tokyo - 23 Wards |
| Job Type | Temporary |
| Salary | 6 million yen ~ 8 million yen |
Job Description
This role leads front-end basic design and technical decision-making for a large-scale consumer e-commerce marketplace used by millions. You'll translate UI/UX vision into performant, maintainable React/TypeScript experiences while driving reliability, monitoring, and continuous improvement.
Client Details
Our client is a leading, large-scale consumer internet and e-commerce marketplace in Japan, operating mission-critical web services that must remain fast and stable even during peak campaign events. The engineering environment values measurable UI/UX improvements, strong technical leadership, and modern front-end practices.
Description
As a senior-level front-end lead, you will:
- Act as a core project member, delivering design, development, testing, and release for new or existing features
- Translate UI/UX wireframes into high-quality, production-ready code and visual experiences
- Bridge design, user requirements, and technical constraints-owning both "how it looks" and "how it works"
- Make technical decisions under complex conditions for large-scale, high-traffic systems
- Build reusable, flexible, high-performance components and libraries for future use
- Drive system improvement initiatives (refactoring, architecture selection, performance measurement and tuning)
- Optimize front-end performance (e.g., JavaScript performance profiling and improvement)
- Maintain services through monitoring, troubleshooting, bug fixing, and incident reporting in production
- Collaborate closely with designers, backend engineers, and stakeholders to deliver at speed with quality
- Create/maintain documentation such as design documents and test cases
- Apply AI knowledge/tools to improve development efficiency and service quality (e.g., coding assistants, MCP servers)
Job Offer
- Work on a high-scale, consumer-facing e-commerce platform where performance and reliability truly matter
- Ownership of front-end architecture, optimization, and technical direction in a senior capacity
- Collaboration with UI/UX specialists and cross-functional engineering stakeholders
- Strong engineering culture focused on continuous improvement (hypothesis → validation → analysis → systematization)
To apply online please click the 'Apply' button below. For a confidential discussion about this role please contact Serena Wu on +81 3 6627 6137.
General Requirements
| Minimum Experience Level | No experience |
| Career Level | Mid Career |
| Minimum English Level | Fluent |
| Minimum Japanese Level | Basic |
| Minimum Education Level | Bachelor's Degree |
| Visa Status | Permission to work in Japan required |
Required Skills
Must-have experience and skills
- 3+ years' experience as a technical lead (architecture design for high-traffic web systems, technical decision-making)
- Proactive problem-solver who can identify issues, propose solutions via root-cause analysis, and execute
- Strong ability to design front-end architecture from scratch:
- Component-oriented design, state management, design systems, UX principles
- Performance optimization and web delivery/infrastructure concepts (e.g., CDN)
- Hands-on production experience:
- Service monitoring, troubleshooting, and reporting in live environments
- 5+ years of front-end development with HTML / CSS / JavaScript
- 5+ years using React / Redux / TypeScript
- Testing expertise:
- Unit tests, E2E tests, and integration testing (development + maintenance)
- JavaScript unit testing tools such as Jest / Intern / WDIO
- Strong engineering discipline: performance, maintainability, and security-focused coding and reviews
- Web API integration experience: REST, JSON, CORS
- Solid understanding of parallel/asynchronous processing: AJAX, Promise, WebWorkers, WebSockets
- Linux investigation/operations experience
- Configuration/build management experience: Git, Jenkins (or equivalent)
- DevOps/operations mindset (investigation, analysis, improvement)
- Documentation skills (design docs, test cases)
- Business-level English communication (e.g., TOEIC 800+ equivalent)
- Japanese language: Not required
- Waterfall project management experience (scale: 5+ person-months)
- Agile development experience
- ESLint experience
- Public cloud exposure (e.g., GCP or similar)
Job Location
- Tokyo - 23 Wards
Work Conditions
| Job Type | Temporary |
| Salary | 6 million yen ~ 8 million yen |
| Industry | Software |
