R5 Labs seeks a Senior Front End Developer (React) to contribute to the development of user interfaces for web applications used by major American fintech companies. Key responsibilities involve UI/UX development using React, collaboration with cross-functional teams, optimization for performance, thorough testing and debugging, and direct client engagement to understand and implement requirements. The ideal candidate possesses 3+ years of front-end experience, expertise in React and JavaScript/TypeScript, a strong understanding of functional programming and design-driven development, and experience with statically-typed languages. The role requires excellent communication and collaboration skills and a passion for quality software development.