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Senior Front-End Tech Lead - Build High-Traffic E‑Commerce UX

Tokyo 23 Wards Temporary ¥6,000,000 - ¥8,000,000 per year Foreign Multinational View 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.
  • Own front-end architecture for a massive, high-traffic platform.
  • Lead performance, reliability, and AI-driven engineering improvements.

About Our Client

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.

Job 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)

The Successful Applicant

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

Nice-to-have

  • Waterfall project management experience (scale: 5+ person-months)
  • Agile development experience
  • ESLint experience
  • Public cloud exposure (e.g., GCP or similar)

What's on 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)



Contact
Serena Wu
Quote job ref
JN-052026-7019821
Phone number
+81 3 6627 6137

Job summary

Function
IT
Specialisation
Programming / Development
Specialisation
Technology & Telecoms
Location
Tokyo 23 Wards
Job Type
Temporary
Consultant name
Serena Wu
Consultant phone
+81 3 6627 6137
Job Reference
JN-052026-7019821
Company Type
Foreign Multinational

Diversity & Inclusion at Michael Page

We don't just accept difference - we celebrate it. We encourage applicants from all backgrounds to apply for this role and are committed to building inclusive, diverse workplaces where everyone can thrive. If you require any support or reasonable adjustments during the recruitment process, please let us know.