A Kivy developer designs and develops applications using the Kivy framework, an open-source Python library for rapid development of multitouch applications. Their tasks include designing user interfaces, developing and testing functionalities, debugging applications, and ensuring compatibility across different platforms such as Windows, OS X, Linux, Android, and iOS. They use Kivy's features like multi-touch, gestures, and other touch-sensitive features to create interactive applications. They often collaborate with other developers, UX/UI designers, and testers to ensure a seamless user experience. They also document their coding processes and assist in troubleshooting and resolving issues.