Develop Native iOS Applications with Swift and SwiftUI

This skill turns an agent into an expert iOS developer specializing in native app development across the Apple ecosystem, mastering Swift 6 (including strict concurrency and typed throws), SwiftUI's declarative UI framework with iOS 18 enhancements, and hybrid UIKit/SwiftUI architectures. Its core development coverage spans iOS 18 API integrations, Xcode 16 workflows, Swift Package Manager dependency management, and scene-based app lifecycle handling; SwiftUI mastery adds state management (@State, @Binding, @ObservedObject, @StateObject), Combine-based reactive programming, custom view modifiers, navigation and coordinator patterns, and accessibility-first, performance-tuned view building. It handles UIKit interoperability, wrapping UIViewController and UIView, diffable-data-source collection and table views, and legacy migration to SwiftUI, and applies architecture patterns including MVVM with Combine, Clean Architecture, the coordinator pattern, repository-based data abstraction, and dependency injection via Swinject or custom solutions. Data persistence covers Core Data with @FetchRequest, SwiftData for iOS 17+, CloudKit sync, Keychain Services, and SQLite or FMDB for complex databases; networking covers URLSession with async/await, Combine publishers, Codable-based REST integration, Apollo iOS for GraphQL, WebSockets, and certificate pinning. Performance work uses Instruments profiling, Core Animation optimization, image-caching libraries like SDWebImage or Kingfisher, lazy loading and pagination, and GCD-based thread and battery management. Security coverage spans Keychain storage, Touch ID and Face ID biometric authentication, App Transport Security configuration, and App Tracking Transparency compliance, while testing spans XCTest, XCUITest, TDD, snapshot testing, and Xcode Cloud CI with TestFlight beta distribution. It also manages App Store Connect submission, ASO metadata and screenshot optimization, privacy nutrition labels, and enterprise MDM distribution, plus advanced platform features - home-screen and lock-screen widgets, Live Activities and Dynamic Island, SiriKit, Core ML and Create ML, ARKit, Core Location and MapKit, HealthKit, and HomeKit - and cross-device integration via Apple Watch connectivity, watchOS apps, Mac Catalyst, AirDrop, Handoff, iCloud, and Sign in with Apple. DevOps coverage includes Xcode Cloud, Fastlane, GitHub Actions or Bitrise pipelines, automated code signing, and crash reporting via Crashlytics or Sentry. Accessibility work covers VoiceOver, Dynamic Type, high-contrast and reduced-motion support, and Voice Control or Switch Control compatibility. Its response approach analyzes requirements for iOS-specific patterns, recommends SwiftUI-first solutions with UIKit integration where needed, delivers production-ready Swift code with error handling, builds in accessibility from the design phase, and accounts for App Store review guidelines and performance across device types.

Use it for iOS developer tasks or workflows, or when guidance, best practices, or checklists for iOS development are needed - for example building a SwiftUI app with Core Data and CloudKit sync, creating custom UIKit components inside SwiftUI, implementing biometric authentication with fallback handling, designing an accessible data visualization with VoiceOver support, setting up a CI/CD pipeline with Xcode Cloud and TestFlight, profiling performance with Instruments, building Live Activities, or adding ARKit product visualization. Do not use it for tasks unrelated to iOS development or that need a different domain or tool outside this scope.

Input is an iOS development task, architecture question, or feature request. Output is production-ready Swift code, SwiftUI-first with UIKit integration where needed, with proper error handling, accessibility considerations built in from the design phase, and App Store compliance and performance accounted for; for detailed worked examples, the skill opens resources/implementation-playbook.md.

iOS developers and teams who need production-ready Swift and SwiftUI code and architecture guidance across the full Apple ecosystem - from Core Data and networking to App Store submission, accessibility, and watchOS or Mac Catalyst distribution - without hand-rolling best practices for each area separately.