| name | swift-patterns |
| description | Swift architecture reference — SwiftUI, UIKit, Combine, async/await, actors, and production best practices for Swift 5.9/6.0 (2024-2025). Use when making architectural decisions, reviewing Swift code, or selecting libraries. Also use when the user mentions iOS development, macOS apps, or Apple platform development. |
| user-invocable | true |
| argument-hint | [frameworks|patterns|architecture|practices|features|all] |
Swift Architecture Patterns
Swift architecture reference for Claude Code. Covers frameworks, design patterns, concurrency, architecture, and best practices for Swift 6.0-6.2 (2024-2025).
When to use this skill
- Making architectural decisions in Swift projects
- Reviewing Swift code for idioms and best practices
- Selecting frameworks or crates for iOS, macOS, server-side, or embedded Swift
- Understanding Swift concurrency (async/await, actors, structured concurrency)
Decision Framework
Platform selection
| Scenario | Default choice | Why |
|---|
| iOS/iPadOS/macOS app | SwiftUI + SwiftData | Apple's modern declarative stack |
| Complex state management | TCA (Composable Architecture) | Unidirectional, testeable, composable |
| Simple MVVM | @Observable + SwiftUI | Apple-recommended, minimal boilerplate |
| Server-side API | Vapor 4 | Most mature Swift server framework |
| Lightweight server | Hummingbird 2 | Fast, modular, fewer dependencies |
| Serverless (AWS) | Swift AWS Lambda Runtime | Native Lambda support |
| Persistence (iOS 17+) | SwiftData | Core Data successor, @Model macro |
| Persistence (legacy) | GRDB.swift | Best SQLite wrapper for Swift |
| Testing | Swift Testing | New framework (Swift 6), @Test, #expect |
| DI | Factory | Property-wrapper based, compile-time safe |
Complexity tiers
- Simple screen: MV pattern —
@Model directly in View
- Feature with logic: MVVM with
@Observable ViewModel
- Complex app: TCA or Clean Architecture with UseCases
- Enterprise/team: Clean Architecture + DI (Factory/Needle)
Swift Evolution (Key Versions)
| Version | Date | Key features |
|---|
| 5.9 | Sep 2023 | Macros, parameter packs, if/switch expressions |
| 6.0 | Sep 2024 | Data race safety compile-time, Embedded Swift, Swift Testing, unified Foundation |
| 6.1 | Mar 2025 | Package traits, background indexing, nonisolated on types |
| 6.2 | Sep 2025 | Approachable Concurrency, WebAssembly beta, Swift-Java bridge, Observations |
Production Results
| Company | Migration | Result |
|---|
| Apple (Password Monitoring) | Java → Swift | 40% perf improvement, 50% less K8s capacity, 85% less code |
| Duolingo | ObjC → Swift | 100% Swift + SwiftUI, faster iteration |
| Lyft | Mixed → Swift backend | High-perf services with Vapor |
| NSA/CISA | — | Recommends Swift for memory-safe critical code |
Supporting files
frameworks.md — Frameworks and libraries by domaindesign-patterns.md — Swift-idiomatic design patternsarchitecture.md — Architecture patterns (TCA, MVVM, Clean)best-practices.md — Concurrency, error handling, testinglanguage-features.md — Unique Swift features (actors, macros, protocols)
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