# Expo — Universal Native Apps for iOS, Android & Web

> Expo is an open-source framework and platform for making universal React Native apps. Ship to iOS, Android, and web from one codebase — OTA updates, managed workflow, EAS Build cloud service, and 100+ prebuilt native modules.

## Install

Save as a script file and run:

## Quick Use

```bash
npx create-expo-app@latest my-app
cd my-app
npm start      # Metro bundler + QR code
```

Scan the QR with Expo Go app on your phone, or run:
```bash
npm run ios      # iOS simulator
npm run android  # Android emulator
npm run web      # Browser
```

A component:
```tsx
import { Text, View, Button } from "react-native";
import * as Haptics from "expo-haptics";

export default function App() {
  return (
    <View style={{ flex: 1, justifyContent: "center" }}>
      <Text>Hello from Expo</Text>
      <Button
        title="Haptic!"
        onPress={() => Haptics.impactAsync()}
      />
    </View>
  );
}
```

## Intro

Expo is an open-source framework and platform for universal React Native apps. Makes React Native development 10x easier: no Xcode/Android Studio setup required, OTA updates, cloud builds (EAS), and 100+ prebuilt native modules.

- **Repo**: https://github.com/expo/expo
- **Stars**: 48K+
- **Language**: TypeScript
- **License**: MIT

## What Expo Does

- **Managed workflow** — develop without touching native code
- **Expo Go app** — preview on device via QR code
- **EAS Build** — cloud-build iOS/Android binaries
- **EAS Submit** — submit to App Store/Play Store
- **EAS Update** — OTA JS updates (skip store review)
- **Expo Router** — file-based routing (like Next.js)
- **100+ modules** — camera, notifications, location, sensors, biometrics
- **Web support** — same code runs in browser via react-native-web

## Architecture

Expo sits on top of React Native. Managed workflow uses `expo prebuild` to generate native projects on demand. Bare workflow exposes full native access. Expo Router uses file-system routing with shared layouts.

## Self-Hosting

CLI is free and open source. EAS (build/submit/update) is a paid SaaS with free tier. You can self-host EAS Update via `expo-updates` + your own CDN.

## Key Features

- File-based routing (Expo Router)
- Hot reload on device
- OTA updates (EAS Update)
- Cloud builds (EAS Build)
- Web support (react-native-web)
- 100+ first-party modules
- TypeScript-first templates
- Dev Client for native testing

## Comparison

| Framework | Approach | Native Access | Cloud Build |
|---|---|---|---|
| Expo | Managed + bare | Full (prebuild) | EAS |
| Bare RN | Manual | Full | Manual |
| Flutter | Dart + Skia | Full | Codemagic |
| Capacitor | Web in WebView | Plugin | Ionic Hub |

## 常见问题 FAQ

**Q: Expo vs Bare React Native？**
A: Expo 是默认推荐。Bare 只在需要深度原生定制（自定义 ObjC/Swift/Java/Kotlin 代码）时选择。

**Q: 支持 Web 吗？**
A: 支持。同一套代码通过 `react-native-web` 在浏览器运行。适合中后台 + App 同构。

**Q: EAS 贵吗？**
A: 免费层够小团队用（每月 30 次 Build、无限 Update）。商业项目 $19/月 起。

## 来源与致谢 Sources

- Docs: https://docs.expo.dev
- GitHub: https://github.com/expo/expo
- License: MIT

---
Source: https://tokrepo.com/en/workflows/ee9542c4-3577-11f1-9bc6-00163e2b0d79
Author: Script Depot