Senior UI Designer (Contract)

This is a 1 year contract position Rakuten is a leading global e-commerce company. Our mission is to contribute to society by creating value through innovation and entrepreneurship At Rakuten, we drive disruptive innovation, engaging knowledge, creativity and passion from around the world to achieve ambitious goals and help build communities in which people can pursue their dreams and live in happiness. Role Summary We are looking for a highly skilled UI Developer with strong expertise in React and TypeScript to design, develop, and maintain scalable, high-performance web applications. The ideal candidate should possess solid front-end architecture knowledge, experience integrating with backend services through REST APIs, and a strong understanding of testing practices and modern development workflows. The candidate will collaborate closely with Product Managers, UX Designers, Backend Engineers, and Architects to deliver high-quality user experiences and contribute to the overall technical direction of the platform. Key Responsibilities • Design, develop, and maintain responsive and scalable web applications using React and TypeScript. • Translate UI/UX designs into clean, maintainable, and reusable code. • Integrate front-end applications with backend services using RESTful APIs. • Collaborate with backend teams to define API contracts and ensure seamless integration. • Design reusable UI components and shared libraries to improve development efficiency. • Participate in architecture discussions and contribute to front-end technology decisions. • Optimize application performance, accessibility, security, and responsiveness. • Write comprehensive unit, integration, and end-to-end tests. • Perform code reviews and mentor junior developers on best practices. • Troubleshoot and resolve production issues while ensuring system stability. • Work closely with DevOps and QA teams to support CI/CD pipelines and quality initiatives. • Contribute to Agile ceremonies including sprint planning, estimation, and retrospectives. Required Skills & Qualifications Front-End Development • 5+ years of experience in front-end development. • Strong proficiency in JavaScript (ES6+) and TypeScript. • 3+ years of hands-on experience with React. • Experience with React Hooks, Context API, state management patterns, and component lifecycle. • Strong understanding of HTML5, CSS3, SCSS, and responsive design principles. • Experience with modern UI frameworks such as Material UI, Ant Design, or similar. ​ API Integration • Strong experience consuming and integrating REST APIs. • Experience handling authentication mechanisms such as JWT, OAuth, or SSO. • Knowledge of API error handling, retry mechanisms, caching, and performance optimization. • Ability to collaborate effectively with backend teams on API design and troubleshooting. Front-End Architecture • Strong understanding of UI architecture patterns and scalable application design. • Experience designing modular and reusable component libraries. • Knowledge of Micro Frontend architecture is a plus. • Understanding of application security best practices and performance optimization techniques. • Familiarity with browser rendering, network optimization, and frontend performance monitoring. Testing & Quality • Experience with testing frameworks such as: • Jest • React Testing Library • Cypress or Playwright • Experience implementing automated testing strategies and maintaining test coverage. • Familiarity with mocking APIs and integration testing approaches. Development Practices • Experience with Git and modern branching strategies. • Familiarity with CI/CD pipelines and automated deployment processes. • Experience working in Agile/Scrum environments. • Strong debugging and problem-solving skills. Rakuten is an equal opportunities employer and welcomes applications regardless of sex, marital status, ethnic origin, sexual orientation, religious belief or age.