Frontend Software Engineer (Mid/Sr)

Kozocom is on a mission to solve corporate issues and create social value through our business.

Responsibilities

Develop and maintain modern web applications using React.js, TypeScript, and modern frontend technologies.
Build reusable, maintainable, and scalable UI components.
Implement Technical SEO best practices to improve website visibility and performance.
Collaborate with UI/UX Designers to transform Figma designs into responsive, pixel-perfect web applications.
Collaborate with Backend Developers to integrate RESTful APIs and third-party services.
Optimize application performance, accessibility, responsiveness, and user experience.
Participate in migrating and modernizing legacy frontend systems to React.js.
Troubleshoot and debug production issues, optimize frontend performance based on monitoring metrics, and continuously improve application reliability.
Write clean, maintainable, and well-documented code following engineering best practices.
Participate in code reviews and help improve coding standards.
Apply AI tools to support coding, refactoring, and documentation when appropriate.
Continuously explore and adopt emerging technologies, AI-Driven Development practices, and AI-powered engineering tools to improve software quality, accelerate development, and enhance engineering productivity.

3+ years of frontend development experience.
Strong proficiency in React.js and TypeScript.
Experience with Next.js.
Experience with modern frontend architectures and component-based development.
Good understanding of HTML5, CSS3, JavaScript (ES6+).
Experience integrating RESTful APIs.
Experience building responsive, cross-browser-compatible applications.
Strong understanding of: Clean Code, Design Patterns, Component Design, State Management, Performance Optimization.
Experience with state management libraries (Redux Toolkit, Zustand, TanStack Query).
Experience integrating APIs, handling asynchronous data, and error handling.
Proficient in Git and Agile/Scrum workflows.
Ability to read and understand technical documentation in English.
Experience using AI coding assistants such as GitHub Copilot, Cursor, Claude Code, Gemini CLI, or similar tools.
Ability to create and maintain AI Agent Skills, prompts, or AI workflows to improve engineering productivity.

Preferred Qualifications

Experience with project planning, task estimation, team coordination, or software project management.
Experience working with Japanese or international clients.
Experience integrating AI services into web applications.
Ability to review architecture and standardize the codebase.
Experience building Design Systems / Component Libraries.
Experience with Micro-Frontend or monorepo (Turborepo, etc.).
Experience mentoring or leading a small team.
Experience with React Native or cross-platform development is a plus.

Soft Skills

Compensation & Benefits
- Competitive salary & salary reviews twice a year
- 13th-month salary
- 19 days of paid leave per year
Health & Well-being
- Premium healthcare insurance for employees and eligible family members
- Annual health check-up
Learning & Career Growth
- Sponsored professional certifications and training programs
- English courses to support continuous learning
- Clear career roadmap and growth opportunities
- Onsite Opportunities: work with international teams and Japanese clients
Work Environment & Culture
- 40-hour work week (Monday – Friday)
- Flexible hybrid working policy
- Happy, inclusive, and open-minded working culture
- Working equipment (MacBook/ThinkPad, depending on project requirements)
- Long-service recognition program after 5-year milestones
- Free snacks, coffee and beverages in the pantry
- Annual company trip and team-building activities
- Sports clubs and internal activities (Football, Badminton, etc.)

To apply, please send your CV to: kzvn-hr@kozo-japan.com