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 platformHands-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 supportTokyo 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 architectureBuild reusable components and component-driven design systems that scale with the productDevelop high-performance visual tools using HTML5 Canvas, WebGL, OffscreenCanvas, and Web Workers for asset previews, editing, and annotationCollaborate closely with backend and AI teams to integrate APIs and real-time workflowsOwn 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 experienceStrong 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 casesStrong grasp of state management, styling solutions, performance optimization, and building reusable design systems, with attention to code quality, error handling, logging, and internationalizationExperience 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 agentsFrontend performance optimization for high-concurrency and large-data-volume scenariosCanvas/WebGL data visualization experience, including diagnosing frame rate drops, memory leaks, and overdrawActive open-source contributions on GitHub or a technical blog with high-quality frontend content