An iOS Tech Certified Developer primarily designs, develops, and maintains applications for Apple's iOS platforms. They use programming languages such as Swift and Objective-C to create user-friendly and functional mobile applications. They are responsible for translating technical requirements into code, testing and debugging applications, collaborating with cross-functional teams to define app features, and ensuring quality and performance. They also need to keep up-to-date with new technology trends, iOS updates, and coding standards. Furthermore, they may be involved in the app deployment process, ensuring it meets Apple's guidelines for the App Store.