A GUI framework developer designs and builds user interface tools and applications to enhance user interaction. They use GUI frameworks such as Qt, GTK, or JavaFX to develop visually appealing and user-friendly interfaces for software or websites. Their responsibilities include creating and implementing interactive elements, debugging applications, improving system performance, and ensuring compatibility across different platforms and devices. They work closely with UX/UI designers and backend developers, turning design concepts into functional interfaces. They also conduct user testing to identify issues and make necessary adjustments, ensuring the final product provides an optimal user experience.