What database is used for iOS apps?

It’s really neither . It’s app development. Front and backend development is mainly centered around the web, with front end being all the stuff that happens on the client and the backend all the stuff on the server.

The answer is both. Swift can be used to build software that runs on the client (frontend) and the server (backend) . Most modern iOS (and iPadOS), tvOS, macOS, and watchOS applications are written in Swift, proving that it is an excellent programming language for frontend development.

The 3 Best Databases for iOS Apps