Overview

Learn about Expo CLI, the command-line tool for developing Expo applications.

Expo CLI is the official command-line interface for Expo projects. It provides a comprehensive set of tools for developing, building, and deploying React Native applications with Expo.

What is Expo CLI?

Expo CLI is distributed as the @expo/cli npm package and serves as the primary interface for:

• Starting development servers with Metro bundler
• Building and running native applications locally
• Generating native iOS and Android projects
• Managing dependencies compatible with your Expo SDK version
• Exporting production-ready bundles
• Authenticating with your Expo account

The CLI is designed with a lean, intentional public interface where all commands and arguments are carefully considered.

Main Features

Development Server

The CLI provides a powerful development server with Metro bundler integration that supports:

• Multi-platform bundling (iOS, Android, and Web)
• Hot Module Replacement (HMR)
• Fast Refresh for instant updates
• Chrome DevTools Protocol for debugging
• TypeScript support with automatic type generation
• Server-side rendering and API routes

Native Development

Build and run your app on iOS simulators, Android emulators, and physical devices:

• Automatic device detection and selection
• Xcode and Gradle build integration
• Code signing management for iOS
• Variant and configuration support

Project Management

• Generate native projects with expo prebuild
• Install compatible dependencies with expo install
• View resolved configuration with expo config
• Customize Metro bundler and native projects

Common Workflows

Starting Development

npx expo start

Opens an interactive terminal UI where you can:

• Press i to open iOS simulator
• Press a to open Android emulator
• Press w to open in web browser
• Scan QR code with Expo Go or development build

Building Locally

# Build and run on iOS
npx expo run:ios

# Build and run on Android
npx expo run:android

These commands compile your native code and launch the app on a simulator/emulator or physical device.

Generating Native Projects

npx expo prebuild

Creates ios/ and android/ directories with native code that you can open in Xcode or Android Studio.

Installing Dependencies

npx expo install react-native-maps

Installs packages with versions compatible with your Expo SDK version.

Exporting for Production

npx expo export

Creates optimized production bundles for deployment, including:

• Minified JavaScript
• Compressed assets
• Platform-specific bundles
• Static HTML for web

Requirements

• Node.js 20.19.4 or newer (LTS version recommended)
• npm, yarn, pnpm, or bun package manager
• For iOS development: macOS with Xcode (not supported on Windows)
• For Android development: Android Studio or Android SDK

Getting Help

Run any command with the --help flag to see detailed usage information:

npx expo start --help
npx expo run:ios --help
npx expo prebuild --help

Environment Variables

Expo CLI supports various environment variables for customization:

• EXPO_DEBUG=1 - Enable debug logging
• EXPO_OFFLINE=1 - Skip network requests
• CI=1 - Run in non-interactive CI mode
• EXPO_NO_TELEMETRY=1 - Disable analytics

See the Environment Variables page for a complete list.