A Full Stack Developer works on both front-end and back-end of websites or applications. They handle tasks such as creating user interfaces, integrating backend data, server and database management, and implementing design principles to build a responsive and optimized website or application. They are knowledgeable in several programming languages like JavaScript, HTML, CSS for front-end and Python, Ruby, Java for back-end. They also work with frameworks like Angular, React, Django, and databases like SQL, MongoDB. Their job is to understand customer requirements and build a comprehensive, efficient, and user-friendly web solution.