Freelance Senior OR Junior Full Stack Developer – React / Next.js / Node.js – Barcelona

You will collaborate closely with the Tech Lead, Product Owner, UX Designer, and Data team to design, develop, and deliver high-quality features within an agile environment.

• Develop and maintain complex, data-heavy user interfaces using React and Next.js
• Build and optimise reusable components and contribute to the internal UI library
• Design and integrate REST APIs and WebSocket endpoints
• Ensure code quality through clean architecture and best practices
• Write unit and integration tests (Jest / Testing Library)
• Collaborate with Product, UX, and Data to deliver features end-to-end
• Participate in architecture discussions and decision-making
• Troubleshoot and resolve issues across the stack
• Contribute to CI/CD processes and development wo...