A MERN stack developer job description involves designing, developing, and maintaining web applications using MongoDB, Express.js, React, and Node.js. Key responsibilities include front-end development with React, back-end development with Node.js/Express.js, database management with MongoDB, and API development. The role requires strong problem-solving, debugging skills, and collaboration with cross-functional teams to deliver high-quality applications. Experience: Proven experience in full-stack development, potentially with Redux for state management.