Is it possible to implement interface display without using layers in the application architecture?

Technically, it is possible to implement interface display without explicit layer separation, but it is not recommended. Layers in application architecture (for example, Presentation, Domain, Data) help structure the code, divide responsibilities, and simplify maintenance.

If layers are not used, the interface logic, business rules, and data access can become mixed, leading to complex and hard-to-maintain code.

In iOS, for example, you can create a ViewController that contains display logic, business logic, and network operations all at once, but this quickly complicates the project. Therefore, architectural patterns (MVC, MVVM, VIPER) are usually used, which imply separation into layers.