We are looking for a Frontend Developer specialized in React.js to join our client's team carrying out a project for one of the EU institutions to design, build, and maintain modern, scalable web applications. You will work closely with product owners, UX designers, and backend engineers to deliver high-quality, testable, and maintainable user interfaces. You will contribute to the full development lifecycle, from design and implementation to testing, CI/CD integration, and continuous improvement.IMPORTANT: Please note that this job would require you to initiate the process of getting a Security Clearance certificate. We will be happy to give you more details during the interview.Key Responsibilities• Design and develop responsive, high-performance user interfaces using React.js• Translate UX/UI designs and functional requirements into clean, reusable code• Apply frontend architecture best practices (componentization, separation of concerns, state management)• Write unit tests and component tests to ensure code reliability and regression prevention• Participate in code reviews and enforce coding standards• Use GitLab for version control, merge requests, and CI/CD pipelines• Collaborate with backend teams to integrate REST APIs and asynchronous services• Optimize applications for performance, accessibility, and security• Actively contribute to continuous improvement of development processes and toolingTechnical Skills & RequirementsMandatory• Strong experience with React.js (functional components, hooks)• Proficiency in JavaScript (ES6+) and TypeScript• Solid understanding of HTML5, CSS3, and modern layout techniques (Flexbox, Grid)• Experience with Git and GitLab workflows (branches, merge requests, CI pipelines)• Strong experience in unit testing (Jest, React Testing Library or equivalent)• Knowledge of frontend development best practices:o Clean code and maintainabilityo Reusable componentso Proper state and lifecycle managemento Error handling and loggingNice to Have• Experience with CI/CD pipelines in GitLab• Familiarity with linting and quality tools (ESLint, Prettier)• Knowledge of accessibility standards (WCAG)• Experience with performance optimization and browser debugging tools• Exposure to Agile / Scrum methodologiesQuality & Engineering Practices• Write testable and well-documented code• Maintain high unit test coverage• Follow coding standards and naming conventions• Ensure security and performance best practices• Actively participate in technical reviews and retrospectivesSoft Skills• Strong communication and collaboration skills• Ability to work autonomously and take ownership• Attention to detail and quality-driven mindset• Willingness to learn and adapt to evolving technologiesEducation & Experience• Degree in Computer Science, Software Engineering, or equivalent experience• Proven experience as a Frontend Developer in a professional environmentWhat We Offer: B2B contract signed directly with the client Remote work setup with one visit per month to the Luxembourg office (2–3 days) Rate: 430-460 EUR/day