An Apple Certified iOS Mobile Devices developer designs, develops, and maintains applications for iOS platforms. They ensure the performance, quality, and responsiveness of applications, collaborate with cross-functional teams to define, design, and ship new features, and identify and correct bottlenecks and fix bugs. They help maintain code quality, organization, and automatization. They stay up-to-date with new technology trends, applications, and programming languages. The certification validates their proficiency in using Apple's iOS SDK, Xcode, and Swift or Objective-C to build and deploy iOS applications, ensuring they meet Apple's standards for safety, performance, and design.