Structure an iOS app that stays testable as it grows. MVVM with an observable view model, reactive pipelines with Combine, dependency injection through protocols, local persistence with UserDefaults, Keychain, and Core Data / SwiftData, networking with URLSession and Codable, and testing the whole stack.
Before you start
This is the layer that ties everything together — take the Swift, iOS Development, and SwiftUI courses first.
MVVM in SwiftUI
Separate what the screen shows from how it looks. A view model holds UI state and logic as an observable object; the view renders it and sends events. Learn MVVM and unidirectional data flow.
Reactive Pipelines with Combine
Combine is Apple’s reactive framework: values flow through publishers, are transformed by operators, and delivered to subscribers. Learn the model and where it fits alongside async/await.
Dependency Injection
A view model needs a service, which needs a network client. Dependency injection wires this graph and — crucially — lets you swap a real service for a fake in tests. Learn DI with protocols in Swift.
Data Persistence
Store data on the device with the right tool: UserDefaults for small settings, Keychain for secrets, and Core Data or SwiftData for structured, queryable, relational data — plus the file system for blobs.
Networking with URLSession
Talk to a backend with URLSession and async/await, decode JSON straight into Codable models, handle errors properly, and know where a library like Alamofire fits.
Testing iOS Apps
The architecture in this course exists to be testable. Write fast unit tests for view models and services with XCTest and fakes, and cover critical flows with XCUITest UI tests.