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Clean architecture iOS interview questions

Clean architecture questions test whether you understand dependency direction and boundaries, or just the diagram. The senior answer is pragmatic.

The idea and the dependency rule

Clean architecture separates the app into layers, domain and use cases at the center, then interface adapters, then frameworks and UI at the edge, with the dependency rule that source dependencies point inward. The domain knows nothing about SwiftUI, URLSession, or Core Data, so business logic is testable and swappable independent of frameworks.

Where it helps and where it hurts

It pays off in large, long-lived apps where multiple teams and changing frameworks make isolation valuable. In a small app it can add layers and indirection that slow you down for little benefit. The senior framing is to apply the dependency rule where it earns its keep and avoid ceremony where a simpler structure suffices.

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Share Your Screen works topics like this through in full: 75 solved Swift problems with tests, 9 real case studies, and 7 annotated mock interviews, so you rehearse the live round instead of just reading about it.

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Frequently asked

What is the dependency rule in clean architecture?

Source code dependencies point inward toward the domain. Inner layers like use cases never depend on outer layers like UI or frameworks.

Is clean architecture overkill for small apps?

Often yes. Its isolation pays off in large, long-lived codebases. For small apps a simpler structure usually delivers the same benefits with less ceremony.