Expo

Try Expo in the Browser • Read the Documentation • Learn more on our blog • Request a feature

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Introduction

Expo is an open-source platform for making universal native apps that run on Android, iOS, and the web. It includes a universal runtime and libraries that let you build native apps by writing React and JavaScript.

This repository includes the Expo SDK, Modules API, Go app, CLI, Router, documentation, and various other supporting tools. Expo Application Services (EAS) is a platform of hosted services that are deeply integrated with Expo open source tools. EAS helps you build, ship, and iterate on your app as an individual or a team.

Read the Expo Community Guidelines before interacting in the repository. Thank you for helping keep the Expo community open and welcoming!

Table of contents

📚 Documentation

Learn about building and deploying universal apps in our official docs!

🗺 Project Layout

packages All the source code for Expo modules, if you want to edit a library or just see how it works this is where you'll find it.
apps This is where you can find Expo projects which are linked to the development modules. You'll do most of your testing in here.
apps/expo-go This is where you can find the source code for Expo Go.
apps/expo-go/ios/Exponent.xcworkspace is the Xcode workspace. When developing iOS, always open this instead of Exponent.xcodeproj because the workspace also loads the CocoaPods dependencies.
docs The source code for https://docs.expo.dev
templates The template projects you get when you run npx create-expo-app
react-native-lab This is our fork of react-native used to build Expo Go.
guides In-depth tutorials for advanced topics like contributing to the client.
tools contain build and configuration tools.
template-files contains templates for files that require private keys. They are populated using the keys in template-files/keys.json.
template-files/ios/dependencies.json specifies the CocoaPods dependencies of the app.

🏅 Badges

Let everyone know your app can be run instantly in the Expo Go app!

[![runs with Expo Go](https://img.shields.io/badge/Runs%20with%20Expo%20Go-000.svg?style=flat-square&amp;logo=EXPO&amp;labelColor=f3f3f3&amp;logoColor=000)](https://expo.dev/client)

[![runs with Expo Go](https://img.shields.io/badge/Runs%20with%20Expo%20Go-4630EB.svg?style=flat-square&amp;logo=EXPO&amp;labelColor=f3f3f3&amp;logoColor=000)](https://expo.dev/client)

👏 Contributing

If you like Expo and want to help make it better then check out our contributing guide! Check out the CLI package to work on the Expo CLI.

❓ FAQ

If you have questions about Expo and want answers, then check out our Frequently Asked Questions!

If you still have questions you can ask them on our Discord and Forums or X @expo.

💙 The Team

Curious about who makes Expo? Here are our team members!

License

The Expo source code is made available under the MIT license. Some of the dependencies are licensed differently, with the BSD license, for example.

Star the Expo repo on GitHub to support the project

Most popular functions for expo-mail-composer

To help you get started, we’ve selected a few expo-mail-composer examples, based on popular ways it is used in public projects.

expo-mail-composer.composeAsync