macOS App Design & Development

Guide for designing and implementing native-feeling, "good Mac citizen" apps: fast, elegant, accessible, and deeply integrated with macOS workflows.

Two Rules That Beat Everything Else

Prefer system components and conventions over bespoke UI—fastest path to "feels right on Mac"
If you customize bars, backgrounds, borders, or control chrome: stop and justify it

Quick Reference: Mac Citizen Checklist

| Area | Requirement | |------|-------------| | Menu Bar | Standard layout (App/File/Edit/View/Window/Help), ⌘, for Settings | | Keyboard | Every primary command reachable via keyboard, standard shortcuts work | | Windows | Resize fluidly, support multiple windows, respect fullscreen/minimize | | Sidebars | Top-level navigation, scannable items, content extends behind | | Toolbars | Group by function/frequency, demote secondary to "more" menu | | Text | Use system text components, standard editing behaviors | | Accessibility | VoiceOver labels, full keyboard navigation, Reduced Motion support |

Liquid Glass Quick Rules

Do:

Use for navigation/controls layer (toolbars, sidebars, bars)
Let system components provide built-in behaviors

Don't:

Apply to content layer (tables, lists, document content)
Stack "glass on glass"

App Archetypes

Identify your app type first:

Document-based: Files as primary units (open/save/duplicate)
Library + editor: Sidebar lists items, detail in main area
Utility: Single window, optional menu bar
Menu-bar app: Lives in menu bar, minimal UI
Pro tool: Dense, power-user workflows

Deliverables Before Building

App archetype identified
Information architecture (sidebar structure, navigation, window model)
Command map (menus + keyboard shortcuts for every major feature)
State + data model (persistence, undo/redo, concurrency)
Accessibility plan (VoiceOver, keyboard, contrast, reduce motion)

Full Reference

For complete design system details, Icon Composer workflow, SF Symbols guidance, evaluation rubrics, and Definition of Done checklist:

See: references/macos-design-guide.md

Common Mistakes

| Mistake | Fix | |---------|-----| | Missing menu bar commands | Every feature in menus with keyboard shortcuts | | Settings outside App menu | Always ⌘, opening from App menu | | Custom text components | Use system text for Mac editing ecosystem | | Toolbar overload | Demote secondary actions, group by function | | Glass on content | Reserve Liquid Glass for navigation layer only | | Breaking standard shortcuts | Never override ⌘C, ⌘V, ⌘Z, etc. | | Single-window only | Support multiple windows when it benefits workflows |