An Apple Developer designs, develops, and maintains applications for Apple devices. They use Apple's software development environment, Xcode, and programming languages like Swift and Objective-C. They engage in all phases of development, from concept to deployment, ensuring the app abides by Apple's design guidelines. They work on enhancing user experience, debugging, and improving app functionality. They also collaborate with cross-functional teams, such as UI/UX designers, to integrate design elements. Apple Developers need to understand the iOS ecosystem, including iOS SDK and Apple's app review process, to ensure smooth app submission to the App Store.