macOS App Development - Swift 6.3

Build native macOS apps with Swift 6.3 (latest: 6.3.3, bundled in Xcode 26.6, Jun 2026), SwiftUI, SwiftData, and macOS 26 Tahoe (26.6 current). Target macOS 14+ for SwiftData/@Observable, macOS 15+ for latest SwiftUI, macOS 26 for Liquid Glass and Foundation Models. Note Xcode 26.6 still bundles the macOS 26.5 SDK, so 26.6-only API is not yet buildable. For the WWDC 2026 beta stack (macOS 27, Xcode 27, Swift 6.4, shipping fall 2026), see references/fall-2026-releases.md.

Quick Start

import SwiftUI
import SwiftData

@Model
final class Project {
    var name: String
    var createdAt: Date
    // Named ProjectTask, not Task - `Task` would shadow `Swift.Task`
    @Relationship(deleteRule: .cascade) var tasks: [ProjectTask] = []