A Google Dart Developer designs and builds applications using Google's Dart programming language. They are responsible for writing reliable, efficient code that runs on multiple platforms such as web, server, and mobile. They utilize Dart's libraries and frameworks, like Flutter, to create visually appealing and seamless user interfaces. Additionally, they debug and fix issues, optimize performance, and ensure the application's responsiveness. They also collaborate with cross-functional teams, translating UI/UX designs into code. They might also work on integrating third-party APIs and may be involved in testing and deploying applications.