An iPhone development developer designs, builds, and maintains applications for iOS platforms. They collaborate with cross-functional teams to define app features, create compelling device-specific user interfaces and experiences, and ensure the performance, quality, and responsiveness of apps. They also identify and correct bottlenecks and fix bugs, maintaining code quality and automatization. Proficiency in Swift, Objective-C, and Cocoa Touch is crucial. Familiarity with RESTful APIs, UI/UX design standards, and cloud message APIs and push notifications is also important. They often need to integrate apps with back-end services, while adhering to Apple's design principles and interface guidelines.