What is the maximum number of UIWindow instances that can be created in an application?

There is no strict limit on the number of UIWindow instances that can be created in an iOS application. Theoretically, you can create many windows, but in practice, usually only one main window (key window) is used, along with possibly a few additional ones for displaying pop-up elements or external screens.

It is important to remember that each window consumes resources, and an excessive number of windows can negatively impact performance and UX. Usually, one window is sufficient, and additional interfaces are implemented through UIViewController and its hierarchy.

Therefore, the limit is more practical than systemic.