The Sign in with Apple REST API is a web service that connects you to Apple’s authentication servers . … To sign in from a web app or other platform, like Android, use Sign in with Apple JS.
Read moreDoes iPhone have an API?
In the case of the iPhone, there is the language of Objective-C, and the iPhone API is a set of Objective-C methods built by Apple that allow a developer’s app to interact with the iPhone. For example, the iPhone API includes methods for responding to fingers on the touch screen, and methods for drawing to the screen.
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