Haku Chen · Frontend Engineer · Tokyo, Japan
Jan 2026 – Jan 2026 · CI/CD setup and DX improvement.
Fully automated the performance check at production release, catching unintended score regressions before they ship.
Automating performance monitoring in a monorepo and preventing quality regressions at deploy time.
Captured 2026-09Oct 2025 – Present · Frontend lead — architecture, environment setup, implementation.
Released in January 2026 and profitable from the first month, on a maintainable delivery foundation. Development is ongoing.
A new business line requiring integration of multiple rental car providers with inconsistent response formats, plus a scalable delivery foundation built from scratch.
Aug 2025 – Oct 2025 · Frontend lead, owner of the performance effort.
Raised the mobile performance score from 36 to over 85.
Frontend rendering optimization for a core product, aimed at improving search ranking and user experience.
Captured 2026-09Dec 2024 – Jun 2025 · Initiator and implementer.
Reduced FCP/LCP by 4–10 seconds and improved SEO index coverage.
An initiative I started myself to cut ad spend and grow organic traffic, focused on Core Web Vitals and especially FCP.
Jun 2023 – Jun 2024 · Sub-leader — work allocation, planning, environment setup, mentoring.
Clarified the split of responsibility between frontend and backend, improving maintainability and build performance.
Migrating legacy pages page-by-page from EJS templates — where the frontend handled UI only and data binding was managed by a .NET backend — to a React multi-page architecture.
Jan 2023 – Jan 2024 · Lead — initial setup, technology selection, design direction, rollout support.
The design team could work from a shared Figma component library while the frontend team implemented matching components — consistent UI/UX with substantially less duplicated code. The library was in production use before I left, and other members kept extending it.
The company's first cross-project design system, built to unify styles and UI across multiple products and to give the design team a shared component library.
Captured 2026-09Jun 2022 – Jun 2023 · Frontend developer.
Delivered feature improvements to the React project that measurably improved the booking experience.
Maintaining and extending the flight booking product across two coexisting codebases — React and legacy jQuery — while building shared modules usable by both.