What are common mobile app architecture patterns and when would you use each?

Mobile architecture patterns help organize code and separate concerns. **Common patterns:** - **MVC (Model-View-Controller):** Simple separation; View updates from Controller, Model holds data. - **MVVM (Model-View-ViewModel):** Better for reactive UIs (data binding); ViewModel handles presentation logic. - **MVP (Model-View-Presenter):** View is passive; Presenter handles all logic (good for testing). - **Clean Architecture / VIPER:** Strong separation of layers; better for complex apps. **Choose based on:** app complexity, team size, testing needs, and platform (native vs cross-platform). **Interview tip:** Mention state management, dependency injection, and how architecture scales with team growth.