An iOS developer is much more than an app programmer-they're integral at every phase of iOS development, from wireframing the screens of your app and software planning through to user interface (UI) design, coding and integrations, and testing and submission to the App Store. An iOS developer will take specifications for your mobile app project and create a functioning, user-ready iOS application. Well-rounded iOS developers have experience with both design aspects, like UI and UX design, and actual programming like Swift.
iOS developer skills are separated into three levels, usually depending on their experience and the complexity of the apps they've built. Developers start at the junior phase for the first few years, although the number of apps they've developed and the apps' complexity are far more important when you determine the right developer for your project. After working on more complex projects and alongside more experienced developers, they move to an intermediate phase where they can work on more projects independently. A more experienced developer, which we'll call a "senior developer", can not only design and code an app, but they can also handle testing, mobile security, and API integrations.