Frontend Developer

Frontend Engineer (Mid to Senior) – AI SaaS

📍 Tokyo | Office-first Hybrid (4 days office / 1 day remote)

Our client is searching for a talented Frontend Engineer to join a fast-growing AI SaaS company building cutting-edge creative technology for global enterprise brands. This is a high-ownership, product-focused role where you'll build rich, high-performance web experiences for AI-driven content generation, large-scale visual asset management, and real-time creative review.

SUMMARY:

• Product-focused frontend role turning ambiguous product needs into intuitive interfaces and a solid, scalable frontend architecture for an AI-powered creative platform
• Hands-on opportunity to build high-performance visual tools using Canvas and WebGL — including asset previews, editing, and annotation — while owning features end to end from design through production support
• Tokyo office-first hybrid role (4 days in office); fluent English required, Japanese is a plus; open to mid and senior level candidates with 3+ years of frontend experience

RESPONSIBILITIES:

• Translate unclear product requirements into clean, user-friendly interfaces and a well-structured frontend architecture
• Build reusable components and component-driven design systems that scale with the product
• Develop high-performance visual tools using HTML5 Canvas, WebGL, OffscreenCanvas, and Web Workers for asset previews, editing, and annotation
• Collaborate closely with backend and AI teams to integrate APIs and real-time workflows
• Own features end to end — including design, estimation, implementation, performance monitoring, and production support

REQUIREMENTS:

• Bachelor's degree in Computer Science or a related field, with 3+ years of frontend development experience
• Strong proficiency in TypeScript, HTML5, CSS3, ES6+, and Node.js, with deep expertise in at least one mainstream framework (React or Vue.js)
• Solid understanding of HTML5 Canvas and/or WebGL rendering mechanisms and use cases
• Strong grasp of state management, styling solutions, performance optimization, and building reusable design systems, with attention to code quality, error handling, logging, and internationalization
• Experience using AI coding tools in daily development workflows; fluent English for communication and technical documentation (Japanese is a plus)

Nice to Have:

• Experience developing AI products or AI agents
• Frontend performance optimization for high-concurrency and large-data-volume scenarios
• Canvas/WebGL data visualization experience, including diagnosing frame rate drops, memory leaks, and overdraw
• Active open-source contributions on GitHub or a technical blog with high-quality frontend content