Apple's Best Practices for SwiftUI Development with Claude

Research compilation from Apple’s official documentation, WWDC sessions, and developer community insights focused on SwiftUI development best practices for 2025, with emphasis on AI-assisted workflows.

Key Findings

Preview-Driven Development is Central to Apple’s Philosophy

Apple emphasizes that SwiftUI Previews should be at the heart of your development workflow. The ability to quickly iterate on views without running the full app is fundamental to productive SwiftUI development. This is especially important for complex state scenarios where you don’t want to manually navigate through your app to test specific UI states.

Performance is Critical in 2025

With the new SwiftUI Performance Instrument introduced in WWDC 2025, Apple is placing unprecedented emphasis on view body optimization and state management efficiency. The framework now provides 6x faster list loading and 16x faster updates on macOS.

Architecture Should Support Testing and Maintainability

Apple’s guidance consistently emphasizes that making your app more “previewable” inherently makes it more testable and maintainable. This aligns perfectly with modern development practices and AI-assisted coding workflows.

Critical Strategies for Fast Iteration

1. Simplify Data Dependencies

Instead of passing complex CloudKit or Core Data models directly to views, extract only the necessary properties into simple data types. This eliminates the need to initialize expensive data models just to test UI components.

// Avoid: Complex model dependency
struct CollaboratorCell: View {
    @ObservedObject var collaborator: CloudKitCollaborator
}

// Prefer: Simple, testable inputs
struct CollaboratorCell: View {
    let name: PersonNameComponents
    let image: Image
    let status: ConnectionStatus
}

2. Use Development Assets

Apple provides development assets specifically for preview content that won’t ship with your app. This allows you to include comprehensive mock data and test images without affecting your app’s final size.

3. Implement Protocol-Based Abstractions

Create lightweight protocols that define the minimum interface your views need, then provide “design-time” implementations for previews. This pattern allows you to test complex interactions without initializing production dependencies.

protocol CollageProtocol {
    var name: String { get }
    var layout: CollageLayout { get }
    var slots: [SlotProtocol] { get }
}

struct DesignTimeCollage: CollageProtocol {
    let name: String
    let layout: CollageLayout
    let slots: [SlotProtocol]
    
    static let sample = DesignTimeCollage(
        name: "Sample Collage",
        layout: .twoByTwo,
        slots: DesignTimeSlot.samples
    )
}

4. Leverage StateObject for Conditional Initialization

Using @StateObject prevents expensive model initialization during preview compilation, significantly speeding up preview refresh times.

Advanced Techniques for Complex State Testing

Intermediate Preview Containers

Create wrapper views that manage state specifically for previews:

struct InspectorPreview: View {
    @State private var effects = SlotEffects.default
    
    var body: some View {
        Inspector(effects: $effects) {
            effects.saturation = 0.5
        }
    }
}

#Preview {
    InspectorPreview()
}

Multiple Configuration Testing

Use preview groups to test different states, device sizes, and accessibility settings simultaneously:

#Preview("Multiple States") {
    Group {
        ContentView(state: .loading)
            .previewDisplayName("Loading")
        
        ContentView(state: .loaded(data))
            .previewDisplayName("Loaded")
        
        ContentView(state: .error(SampleError()))
            .previewDisplayName("Error")
    }
}

On-Device Preview Testing

Apple’s enhanced on-device preview system allows real-time interaction testing across multiple devices.

Performance Optimization

View Body Optimization

Keep view bodies fast by moving expensive computations out of view bodies
Use computed properties wisely with caching for formatted strings and complex calculations
Profile with the new SwiftUI Performance Instrument to identify bottlenecks

State Management Efficiency

Design granular data dependencies so views only update when their specific dependencies change
Avoid shared mutable state when possible
Be cautious with Environment for frequently changing values

List Performance

Take advantage of lazy containers (LazyVStack, LazyHStack, LazyVGrid) and the new 6x faster list loading capabilities.

Modern SwiftUI Architecture (2025)

Liquid Glass Design System

The new visual design language with glass-morphic effects requires adoption of new toolbar spacer APIs and cross-platform consistency considerations.

Granular State Management

Design data flows so views only update when their specific dependencies change, leveraging the new SwiftUI Performance Instrument for optimization.

AI-Assisted Development Integration

Structure code to work effectively with AI assistants by:

Using modular, clear component interfaces
Providing comprehensive preview scenarios
Following consistent patterns that AI can recognize and extend

Working with Claude for SwiftUI Development

Structuring Requests

Break down complex UI requirements into smaller, manageable components
Provide detailed requirements including state management needs
Include specific examples of desired behavior and edge cases

Use iterative improvement rather than complete solutions
Ensure AI-generated code follows established patterns
Always test AI-generated code with comprehensive previews

Pattern Consistency

The research emphasizes that a “previewable app is a testable app, and a testable app is a maintainable app.” This principle becomes even more important when working with AI assistants, as clear patterns and constraints help generate better, more consistent code.

Key Insight

Apple’s 2025 SwiftUI guidance centers on the philosophy that preview-driven development creates inherently better architecture. By structuring apps for previewability, developers create code that is more testable, maintainable, and suitable for AI-assisted development workflows. The investment in proper preview architecture pays dividends in development speed, code quality, and team collaboration.

References

Apple Official Documentation & WWDC Sessions

WWDC 2025 - What’s new in SwiftUI
Apple Developer Videos (June 9, 2025)
https://developer.apple.com/videos/play/wwdc2025/256/
WWDC 2025 - Optimize SwiftUI performance with Instruments
Apple Developer Videos (June 9, 2025)
https://developer.apple.com/videos/play/wwdc2025/306/
WWDC 2020 - Structure your app for SwiftUI previews
Apple Developer Videos (June 26, 2020)
https://developer.apple.com/videos/play/wwdc2020/10149/
Previewing your app’s interface in Xcode
Apple Developer Documentation
https://developer.apple.com/documentation/xcode/previewing-your-apps-interface-in-xcode
Human Interface Guidelines
Apple Developer Documentation
https://developer.apple.com/design/human-interface-guidelines

@Previewable Macro & Preview Development

@Previewable: Dynamic SwiftUI Previews Made Easy
SwiftLee (July 8, 2024)
https://www.avanderlee.com/swiftui/previewable-macro-usage-in-previews/
SwiftUI Previewable Macro
Use Your Loaf (iOS 18)
https://useyourloaf.com/blog/swiftui-previewable-macro/

Performance Optimization & Best Practices

Boost Your SwiftUI Workflow with Live Previews in Xcode
Bugfender (March 19, 2025)
https://bugfender.com/blog/swiftui-preview/
WWDC 2025 - Optimize SwiftUI performance with Instruments
Dev.to (June 14, 2025)
https://dev.to/arshtechpro/wwdc-2025-optimize-swiftui-performance-with-instruments-4o4j
A Commonly Overlooked Performance Optimization in SwiftUI
Reddit r/SwiftUI (May 9, 2025)
https://www.reddit.com/r/SwiftUI/comments/1kir4wg/a_commonly_overlooked_performance_optimization_in/

State Management & Architecture

SwiftUI Craftsmanship: State Management
Captain SwiftUI (March 30, 2025)
https://captainswiftui.substack.com/p/swiftui-craftsmanship-state-management
Enhance User Experience with State Management in SwiftUI
Moldstud (February 11, 2025)
https://moldstud.com/articles/p-enhance-user-experience-with-state-management-in-swiftui

Mock Data & Testing Strategies

3 Tips for SwiftUI Previews
Swift and Tips (May 4, 2024)
https://swiftandtips.com/three-tips-to-improve-your-experience-with-swiftui-previews
Previewing Stateful SwiftUI Views
Peter Friese (December 21, 2022)
https://peterfriese.dev/blog/2022/swiftui-previews-interactive/
SwiftUI Previews-based architecture
Thomas Durand’s Blog (March 15, 2024)
https://blog.thomasdurand.fr/story/2024-03-15-preview-based-architecture/
Writing testable code when using SwiftUI
Swift by Sundell (February 17, 2022)
https://www.swiftbysundell.com/articles/writing-testable-code-when-using-swiftui
Dependency Injection in SwiftUI Previews: A Modern Approach
Mehmet Baykar (August 24, 2024)
https://mehmetbaykar.com/posts/dependency-injection-in-swiftui-previews-a-modern-approach/

AI Integration & Developer Tools

Claude Code: Best practices for agentic coding
Anthropic (April 18, 2025)
https://www.anthropic.com/engineering/claude-code-best-practices
I Shipped a macOS App Built Entirely by Claude Code
Indragie Karunaratne (July 1, 2025)
https://www.indragie.com/blog/i-shipped-a-macos-app-built-entirely-by-claude-code
Rewriting a 12 Year Old Objective-C iOS App with Claude Code
Two Cent Studios (June 22, 2025)
https://twocentstudios.com/2025/06/22/vinylogue-swift-rewrite/

Community Resources & Discussions

Tips for improving SwiftUI Preview performance
Reddit r/Xcode (July 3, 2024)
https://www.reddit.com/r/Xcode/comments/1duo4cc/tips_for_improving_swiftui_preview_performance/
How you guys deal with data in the Preview in MVVM?
Reddit r/SwiftUI (October 30, 2023)
https://www.reddit.com/r/SwiftUI/comments/17k5v9a/how_you_guys_deal_with_data_in_the_the_preview_in/
Using PreviewModifier for Quick Xcode Previews
Swiftjective-C (September 30, 2024)
https://swiftjectivec.com/Making-Xcode-Previews-Faster-With-PreviewModifier-in-SwiftUI/

Jeffrey Hicks