A Graphic User Interface (GUI) developer designs and creates software interfaces that users interact with. They focus on aesthetics and usability, ensuring a smooth user experience. Tasks include creating wireframes, storyboards, and prototypes, coding and testing interfaces, and integrating them with back-end systems. They must understand user needs, follow design principles, and know programming languages like JavaScript, CSS, and HTML. GUI developers also work with UX/UI designers and back-end developers, troubleshoot and fix issues, and constantly update and improve interfaces based on user feedback. They play a crucial role in making software or websites intuitive and user-friendly.