> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/expo/expo/llms.txt
> Use this file to discover all available pages before exploring further.

# Expo SDK Overview

> A comprehensive collection of native modules for React Native and Expo applications

# Expo SDK Overview

The Expo SDK is a collection of 100+ native modules that provide access to device and system functionality for React Native and Expo applications. Each module is designed to work seamlessly across iOS, Android, and web platforms.

## What is the Expo SDK?

The Expo SDK provides:

* **Native API Access**: Direct access to device features like camera, sensors, file system, and more
* **Cross-Platform**: Write once, run on iOS, Android, and web
* **TypeScript Support**: Full type definitions for all APIs
* **Modular Architecture**: Install only the modules you need
* **Auto-Configuration**: Most modules auto-configure with `npx expo prebuild`

## Module Categories

### Core Modules

Foundational modules for app architecture and configuration:

* `expo-modules-core` - Module API architecture
* `expo-constants` - System and app constants
* `expo-asset` - Asset management
* `expo-file-system` - File system access
* `expo-font` - Custom font loading

### UI Components

Pre-built UI components with native performance:

* `expo-camera` - Camera access and capture
* `expo-image` - High-performance image component
* `expo-video` - Video playback
* `expo-blur` - Native blur effects
* `expo-symbols` - SF Symbols for iOS

### Device APIs

Access to device hardware and system information:

* `expo-device` - Device information
* `expo-battery` - Battery status
* `expo-sensors` - Accelerometer, gyroscope, etc.
* `expo-haptics` - Haptic feedback
* `expo-brightness` - Screen brightness control

### Data & Storage

* `expo-secure-store` - Encrypted storage
* `expo-sqlite` - SQLite database
* `expo-file-system` - File operations

### Media

* `expo-camera` - Photo and video capture
* `expo-image-picker` - Select from gallery
* `expo-media-library` - Access photo library
* `expo-audio` - Audio playback and recording

### Communication

* `expo-notifications` - Push notifications
* `expo-sharing` - System share sheet
* `expo-sms` - Send SMS messages
* `expo-mail-composer` - Compose emails

## Installation

### Install Individual Modules

```bash theme={null}
npx expo install expo-camera expo-image expo-file-system
```

### Auto-Configuration

Most modules automatically configure native projects:

```bash theme={null}
npx expo prebuild
```

This generates `ios/` and `android/` directories with all required native configuration.

## Basic Usage

```typescript theme={null}
import * as Device from 'expo-device';
import { Image } from 'expo-image';
import * as FileSystem from 'expo-file-system';

function App() {
  // Get device info
  const deviceName = Device.deviceName;
  
  // Use high-performance image
  return (
    <Image 
      source={{ uri: 'https://example.com/image.jpg' }}
      style={{ width: 200, height: 200 }}
    />
  );
}
```

## Version Compatibility

### SDK Versioning

Each Expo SDK version is tied to specific React Native versions:

| Expo SDK | React Native | Release Date |
| -------- | ------------ | ------------ |
| SDK 55   | 0.83.x       | Feb 2024     |
| SDK 54   | 0.82.x       | Jan 2024     |
| SDK 53   | 0.81.x       | Dec 2023     |

### Module Versions

When you install modules with `npx expo install`, the correct versions are automatically selected based on your Expo SDK version.

```bash theme={null}
# Automatically installs compatible versions
npx expo install expo-camera expo-image
```

## Platform Support

Most modules support iOS, Android, and web:

* **iOS**: Full native implementation
* **Android**: Full native implementation
* **Web**: JavaScript implementation or polyfill

<Note>
  Check individual module documentation for specific platform support details.
</Note>

## TypeScript Support

All modules include full TypeScript definitions:

```typescript theme={null}
import * as FileSystem from 'expo-file-system';

// Fully typed
const info: FileSystem.FileInfo = await FileSystem.getInfoAsync(
  FileSystem.documentDirectory + 'test.txt'
);
```

## Bare React Native

Expo modules work in bare React Native projects:

```bash theme={null}
npx install-expo-modules@latest
npx expo install expo-camera
```

## Module Architecture

Expo modules are built on `expo-modules-core`, which provides:

* **Swift API**: Write iOS modules in Swift
* **Kotlin API**: Write Android modules in Kotlin
* **JavaScript API**: Consistent JavaScript interface
* **Auto-Linking**: Automatic native module discovery

See [expo-modules-core](/sdk/modules-core) for architecture details.

## Resources

* [API Reference](https://docs.expo.dev/versions/latest/)
* [GitHub Repository](https://github.com/expo/expo)
* [Expo Documentation](https://docs.expo.dev/)

## Next Steps

* Explore [Core Modules](/sdk/modules-core)
* Browse [UI Components](/sdk/camera)
* Learn about [Device APIs](/sdk/device)