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

1. Prefer system components and conventions over bespoke UI—fastest path to "feels right on Mac"
2. 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

1. App archetype identified
2. Information architecture (sidebar structure, navigation, window model)
3. Command map (menus + keyboard shortcuts for every major feature)
4. State + data model (persistence, undo/redo, concurrency)
5. 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