expo export

Export static files and production bundles for deployment.

The expo export command generates optimized production bundles of your app, creating static files ready for deployment to hosting services or over-the-air (OTA) updates.

Usage

npx expo export [directory] [options]

Arguments

directory · string

Directory of the Expo project. Defaults to the current working directory.

Options

Output Options

--output-dir · string

The directory to export static files to. Default: dist

--platform · string[]

Platforms to export. Options: android, ios, web, all. Default: all. Alias: -p

Build Options

--dev · boolean

Configure static files for developing locally using a non-https server. Disables optimizations.

--no-minify · boolean

Prevent minifying JavaScript source code.

--no-bytecode · boolean

Prevent generating Hermes bytecode for Android. Keeps JavaScript in text format.

Bundler Options

--clear · boolean

Clear the Metro bundler cache before exporting. Alias: -c, --reset-cache

--max-workers · number

Maximum number of tasks to allow the bundler to spawn. Controls parallelization.

Source Maps

--source-maps · string | boolean

Emit JavaScript source maps. Alias: -s

Options:

• true - Generate source maps
• false - No source maps (default)
• inline - Inline source maps in bundle
• external - Generate separate .map files

Web-Specific Options

--no-ssg · boolean

Skip exporting static HTML files and only export API routes for web. Alias: --api-only

--dump-assetmap · boolean

Emit an asset map JSON file for further processing.

What Gets Exported

The export command creates:

• JavaScript bundles - Optimized, minified code for each platform
• Assets - Images, fonts, and other static files
• Metadata - Asset manifests and configuration
• Source maps - Debug information (if enabled)
• HTML files - Static web pages (for web platform)

Examples

Basic Export

Export for all platforms:

npx expo export

Creates dist/ directory with:

dist/
├── assets/          # Images, fonts, etc.
├── bundles/         # JavaScript bundles
│   ├── android-*.js
│   ├── ios-*.js
│   └── web-*.js
├── metadata.json    # Asset metadata
└── index.html       # Web entry (if web platform included)

Specific Platform

Export only for Android:

npx expo export --platform android

Export for iOS and Android only:

npx expo export --platform ios --platform android

Custom Output Directory

Export to a specific directory:

npx expo export --output-dir build

Clear Cache First

Ensure fresh build:

npx expo export --clear

With Source Maps

Generate source maps for debugging:

npx expo export --source-maps

Or specify source map type:

# External .map files
npx expo export --source-maps external

# Inline source maps
npx expo export --source-maps inline

Development Export

Create unoptimized bundles for testing:

npx expo export --dev

This skips:

• Minification
• Bytecode compilation
• Production optimizations

Web API Routes Only

Export only API routes without static HTML:

npx expo export --no-ssg

Useful for:

• Server-side API deployment
• Serverless functions
• Backend-only exports

Without Bytecode

Skip Hermes bytecode compilation:

npx expo export --no-bytecode

Keeps JavaScript in readable format for debugging.

Control Workers

Limit CPU usage during export:

npx expo export --max-workers 2

Platform-Specific Exports

iOS Export

npx expo export --platform ios

Generates:

• iOS-specific JavaScript bundle
• Universal assets (images, fonts)
• Metadata for iOS runtime

Used for:

• OTA updates with expo-updates
• Embedding in iOS binary
• EAS Update deployments

Android Export

npx expo export --platform android

Generates:

• Android-specific JavaScript bundle
• Hermes bytecode (unless --no-bytecode)
• Universal assets
• Metadata for Android runtime

Used for:

• OTA updates with expo-updates
• Embedding in APK/AAB
• EAS Update deployments

Web Export

npx expo export --platform web

Generates:

• Web-optimized JavaScript bundles
• Static HTML files
• Progressive Web App manifest
• Service worker (if configured)
• Web assets

Used for:

• Static site hosting
• CDN deployment
• Server-side rendering

Output Structure

Native Platforms (iOS/Android)

dist/
├── bundles/
│   ├── android-1234567890abcdef.js       # Android bundle
│   ├── android-1234567890abcdef.js.map   # Source map (if enabled)
│   ├── ios-abcdef1234567890.js           # iOS bundle
│   └── ios-abcdef1234567890.js.map       # Source map (if enabled)
├── assets/
│   └── [hash]/                           # Content-addressed assets
│       ├── image.png
│       └── font.ttf
├── metadata.json                         # Asset manifest
└── _expo/                                # Expo metadata
    └── fingerprint

Web Platform

dist/
├── _expo/
│   └── static/
│       ├── js/                           # JavaScript chunks
│       │   ├── web-*.js
│       │   └── *.js.map
│       └── css/                          # Stylesheets
│           └── *.css
├── assets/                               # Static assets
├── index.html                            # Main entry point
├── favicon.ico                           # Favicon
└── manifest.json                         # PWA manifest

Deployment

Hosting Static Web

After exporting for web, deploy to:

Vercel:

npx expo export --platform web
vercel dist

Netlify:

npx expo export --platform web
netlify deploy --dir=dist --prod

GitHub Pages:

npx expo export --platform web
# Commit and push dist/ to gh-pages branch

OTA Updates

Use with expo-updates for over-the-air updates:

# Export for updates
npx expo export

# Serve from update server
# expo-updates will fetch from this endpoint

Or use EAS Update:

eas update --branch production

Embedding in Native Apps

Export and embed in native builds:

# Export native bundles
npx expo export --platform ios --platform android

# Copy to native projects
cp -r dist/bundles/* ios/Generated/
cp -r dist/bundles/* android/app/src/main/assets/

Asset Optimization

Automatic Optimizations

Expo export automatically:

• Compresses images
• Minifies JavaScript
• Tree-shakes unused code
• Content-hashes filenames
• Generates multiple resolutions for images

Asset Map

Generate asset map for custom processing:

npx expo export --dump-assetmap

Creates assetmap.json:

{
  "assets": [
    {
      "path": "assets/icon.png",
      "hash": "abc123...",
      "type": "png",
      "platform": "all"
    }
  ]
}

Source Maps

Why Use Source Maps

Source maps help you:

• Debug production issues
• Get readable stack traces
• Map minified code to source
• Use error reporting tools

Generating Source Maps

npx expo export --source-maps

Uploading to Error Services

Upload source maps to services like Sentry:

# Export with source maps
npx expo export --source-maps

# Upload to Sentry
sentry-cli releases files VERSION upload-sourcemaps dist/bundles

Hermes Bytecode

What is Hermes Bytecode

Hermes bytecode is a binary format that:

• Reduces app startup time
• Decreases bundle size
• Improves performance on Android

Disabling Bytecode

For debugging or compatibility:

npx expo export --no-bytecode

Enabling on iOS

Configure in app.json:

{
  "expo": {
    "ios": {
      "jsEngine": "hermes"
    }
  }
}

Server-Side Generation (SSG)

Static Site Generation

For web, Expo exports static HTML:

npx expo export --platform web

Each route becomes an HTML file:

dist/
├── index.html           # Home page
├── about.html           # /about route
└── blog/
    └── post.html        # /blog/post route

Disabling SSG

Export only client-side JavaScript:

npx expo export --no-ssg

API Routes

API routes are exported as serverless functions:

dist/
└── api/
    └── hello.js        # /api/hello endpoint

Troubleshooting

Export Fails

Clear cache and retry:

npx expo export --clear

Bundle Size Too Large

Analyze bundle size:

EXPO_ATLAS=1 npx expo export

Reduce size by:

• Removing unused dependencies
• Using dynamic imports
• Optimizing images
• Enabling Hermes bytecode

Missing Assets

Ensure assets are properly referenced:

// Good
<Image source={require('./image.png')} />

// Bad (not bundled)
<Image source={{ uri: './image.png' }} />

Source Maps Not Working

Verify source maps are generated:

npx expo export --source-maps
ls dist/bundles/*.map

Hermes Bytecode Issues

Disable if encountering errors:

npx expo export --no-bytecode

Or check Hermes compatibility of dependencies.

Best Practices

Version Control

Don’t commit dist/ directory:

# .gitignore
dist/

CI/CD

Automate exports in CI:

# .github/workflows/export.yml
- name: Export app
  run: npx expo export --platform web

- name: Deploy
  run: vercel dist --prod

Multiple Environments

Use environment variables:

ENV=production npx expo export

Testing Exports

Test exported bundles locally:

npx expo export
npx serve dist

Performance Tips

• Use --max-workers to control CPU usage
• Enable Hermes bytecode for faster startup
• Optimize images before importing
• Use dynamic imports for code splitting
• Enable source maps only when needed