Glossary · Web & App Development
SwiftUI
Overview
What SwiftUI is
SwiftUI is Apple's modern, declarative framework for building user interfaces across all of its platforms — iOS, iPadOS, macOS, watchOS, tvOS, and visionOS — using the Swift programming language. Apple introduced it in 2019 as a newer alternative to UIKit and AppKit.
With a declarative approach, developers describe what the interface should contain and how it should respond to state, and SwiftUI figures out how to render and update it. This tends to produce shorter, more readable UI code than imperative view-by-view manipulation.
How it works
Views are defined as Swift structs that conform to the View protocol and return a description of their content. SwiftUI uses a reactive model: property wrappers such as @State, @Binding, and @Observable connect views to data so that when the data changes, the affected views re-render automatically.
SwiftUI works alongside existing UIKit and AppKit code, so teams can adopt it incrementally within an existing app. Xcode's live preview lets developers see UI changes as they type, speeding up iteration.
When to use it
SwiftUI is a strong default for new apps targeting recent Apple OS versions, especially when a team wants faster UI development and shared code across Apple devices. It is required for some newer platform features and form factors.
Trade-offs remain: some advanced UIKit capabilities still need bridging, and because APIs evolve each year, behavior can differ across OS versions. Apps that must support older OS releases, or need deep low-level control, may still rely on UIKit for parts of the interface. SwiftUI is Apple-only, so cross-platform needs point toward tools like React Native or Flutter.
Where we use it
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How our team puts SwiftUI to work in real projects.
FAQ
SwiftUI — common questions
What is the difference between SwiftUI and UIKit?
UIKit is Apple's older, imperative UI framework where you manage view objects directly; SwiftUI is declarative, so you describe the UI and its state and the framework handles updates. They interoperate, and many apps mix both during a transition.
Which Apple platforms does SwiftUI support?
SwiftUI targets iOS, iPadOS, macOS, watchOS, tvOS, and visionOS, letting developers share much of their UI code across Apple devices. Some features require newer OS versions, so check availability for your minimum deployment target.
Is SwiftUI good for cross-platform apps?
SwiftUI is Apple-only, so it does not target Android or the web. Teams needing a single codebase across Apple and Android platforms typically choose cross-platform frameworks like React Native or Flutter instead.
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