Complete guide for building beautiful apps with Expo Router. Covers fundamentals, styling, components, navigation, animations, patterns, and native tabs.
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name
building-native-ui
description
Complete guide for building beautiful apps with Expo Router. Covers fundamentals, styling, components, navigation, animations, patterns, and native tabs.
Use this skill when you need complete guide for building beautiful apps with Expo Router. Covers fundamentals, styling, components, navigation, animations, patterns, and native tabs.
References
Consult these resources as needed:
references/
animations.md Reanimated: entering, exiting, layout, scroll-driven, gestures
controls.md Native iOS: Switch, Slider, SegmentedControl, DateTimePicker, Picker
form-sheet.md Form sheets in expo-router: configuration, footers and background interaction.
gradients.md CSS gradients via experimental_backgroundImage (New Arch only)
icons.md SF Symbols via expo-image (sf: source), names, animations, weights
media.md Camera, audio, video, and file saving
route-structure.md Route conventions, dynamic routes, groups, folder organization
search.md Search bar with headers, useSearch hook, filtering patterns
storage.md SQLite, AsyncStorage, SecureStore
tabs.md NativeTabs, migration from JS tabs, iOS 26 features
toolbar-and-headers.md Stack headers and toolbar buttons, menus, search (iOS only)
visual-effects.md Blur (expo-blur) and liquid glass (expo-glass-effect)
webgpu-three.md 3D graphics, games, GPU visualizations with WebGPU and Three.js
zoom-transitions.md Apple Zoom: fluid zoom transitions with Link.AppleZoom (iOS 18+)
Running the App
CRITICAL: Always try Expo Go first before creating custom builds.
Most Expo apps work in Expo Go without any custom native code. Before running npx expo run:ios or npx expo run:android:
Start with Expo Go: Run npx expo start and scan the QR code with Expo Go
Check if features work: Test your app thoroughly in Expo Go
Only create custom builds when required - see below
When Custom Builds Are Required
You need npx expo run:ios/android or eas build ONLY when using:
Local Expo modules (custom native code in modules/)
Apple targets (widgets, app clips, extensions via @bacons/apple-targets)
Third-party native modules not included in Expo Go
Custom native configuration that can't be expressed in app.json
When Expo Go Works
Expo Go supports a huge range of features out of the box:
All expo-* packages (camera, location, notifications, etc.)
Expo Router navigation
Most UI libraries (reanimated, gesture handler, etc.)
Push notifications, deep links, and more
If you're unsure, try Expo Go first. Creating custom builds adds complexity, slower iteration, and requires Xcode/Android Studio setup.
Code Style
Be cautious of unterminated strings. Ensure nested backticks are escaped; never forget to escape quotes correctly.
Always use import statements at the top of the file.
Always use kebab-case for file names, e.g. comment-card.tsx
Always remove old route files when moving or restructuring navigation
Never use special characters in file names
Configure tsconfig.json with path aliases, and prefer aliases over relative imports for refactors.
Routes
See ./references/route-structure.md for detailed route conventions.
Routes belong in the app directory.
Never co-locate components, types, or utilities in the app directory. This is an anti-pattern.
Ensure the app always has a route that matches "/", it may be inside a group route.
Library Preferences
Never use modules removed from React Native such as Picker, WebView, SafeAreaView, or AsyncStorage
Never use legacy expo-permissions
expo-audio not expo-av
expo-video not expo-av
expo-image with source="sf:name" for SF Symbols, not expo-symbols or @expo/vector-icons
react-native-safe-area-context not react-native SafeAreaView
process.env.EXPO_OS not Platform.OS
React.use not React.useContext
expo-image Image component instead of intrinsic element img
expo-glass-effect for liquid glass backdrops
Color from expo-router for native semantic colors, not raw PlatformColor (type-safe, auto-adapts to light/dark)
In SDK 56+, never import from @react-navigation/* directly — use expo-router/react-navigation instead (covers @react-navigation/native, /core, /elements, /routers)
Responsiveness
Always wrap root component in a scroll view for responsiveness
Use <ScrollView contentInsetAdjustmentBehavior="automatic" /> instead of <SafeAreaView> for smarter safe area insets
contentInsetAdjustmentBehavior="automatic" should be applied to FlatList and SectionList as well
Use flexbox instead of Dimensions API
ALWAYS prefer useWindowDimensions over Dimensions.get() to measure screen size
Behavior
Use expo-haptics conditionally on iOS to make more delightful experiences
Use views with built-in haptics like <Switch /> from React Native and @react-native-community/datetimepicker
When a route belongs to a Stack, its first child should almost always be a ScrollView with contentInsetAdjustmentBehavior="automatic" set
When adding a ScrollView to the page it should almost always be the first component inside the route component
Prefer headerSearchBarOptions in Stack.Screen options to add a search bar
Use the <Text selectable /> prop on text containing data that could be copied
Consider formatting large numbers like 1.4M or 38k
Never use intrinsic elements like 'img' or 'div' unless in a webview or Expo DOM component
Styling
Follow Apple Human Interface Guidelines.
General Styling Rules
Prefer flex gap over margin and padding styles
Prefer padding over margin where possible
Always account for safe area, either with stack headers, tabs, or ScrollView/FlatList contentInsetAdjustmentBehavior="automatic"
Ensure both top and bottom safe area insets are accounted for
Inline styles not StyleSheet.create unless reusing styles is faster
Add entering and exiting animations for state changes
Use { borderCurve: 'continuous' } for rounded corners unless creating a capsule shape
ALWAYS use a navigation stack title instead of a custom text element on the page
When padding a ScrollView, use contentContainerStyle padding and gap instead of padding on the ScrollView itself (reduces clipping)
CSS and Tailwind are not supported - use inline styles
Colors
Use the Color API from expo-router for native semantic colors. It is a type-safe wrapper over PlatformColor that exposes iOS UIKit colors through Color.ios.* and Android Material 3 colors through Color.android.material.* (static) or Color.android.dynamic.* (adapts to the user's wallpaper on Android 12+). These resolve on-device and automatically adapt to light/dark mode and accessibility settings, so you no longer maintain separate light/dark hex tables or a colors.web.ts file.
Color is platform-specific, so wrap each value in Platform.select with a default hex fallback for web. Centralize the palette in theme/colors.ts and import colors everywhere:
iOS re-resolves these colors automatically when the system theme changes. On Android, call useColorScheme() inside any component that renders them so it re-renders when the theme flips (required when React Compiler memoizes the component).
Don't pass Color / PlatformColor values into Reanimated styles — use static colors there (see references/animations.md).
Platform.select({...})! returns string | OpaqueColorValue. Most React Native style props accept ColorValue (string | OpaqueColorValue) so this works fine. But some third-party props only accept string (e.g. tintColor on expo-image). Cast when needed: colors.label as string.
Text Styling
Add the selectable prop to every <Text/> element displaying important data or error messages
Counters should use { fontVariant: 'tabular-nums' } for alignment
Shadows
Use CSS boxShadow style prop. NEVER use legacy React Native shadow or elevation styles.
