How To Run Expo Cli App In Browser

Assuming that you have Node 12 LTS or greater installed, you can use npm to install the Expo CLI command line utility:

npm
Yarn

Then run the following commands to create a new React Native project called "AwesomeProject":

npm
Yarn

                                                expo init AwesomeProject                  
                                                                    
                                                                    cd                                      AwesomeProject                  
                                                                    npm                                      start                                    # you can also use: expo start

This will start a development server for you.

Running your React Native application

Install the Expo client app on your iOS or Android phone and connect to the same wireless network as your computer. On Android, use the Expo app to scan the QR code from your terminal to open your project. On iOS, use the built-in QR code scanner of the Camera app.

Modifying your app

Now that you have successfully run the app, let's modify it. Open App.js in your text editor of choice and edit some lines. The application should reload automatically once you save your changes.

That's it!

Congratulations! You've successfully run and modified your first React Native app.

Now what?

Expo also has docs you can reference if you have questions specific to the tool. You can also ask for help at Expo forums.

These tools help you get started quickly, but before committing to building your app with Expo CLI, read about the limitations.

If you have a problem with Expo, before creating a new issue, please see if there's an existing issue about it:

in the Expo CLI issues (for issues related to Expo CLI), or
in the Expo issues (for issues about the Expo client or SDK).

If you're curious to learn more about React Native, check out the Introduction to React Native.

Running your app on a simulator or virtual device

Expo CLI allows you to run your React Native app on a physical device without setting up a development environment. If you want to run your app on the iOS Simulator or an Android Virtual Device, please refer to the instructions for "React Native CLI Quickstart" to learn how to install Xcode or set up your Android development environment.

Once you've set these up, you can launch your app on an Android Virtual Device by running npm run android, or on the iOS Simulator by running npm run ios (macOS only).

Caveats

Because you don't build any native code when using Expo to create a project, it's not possible to include custom native modules beyond the React Native APIs and components that are available in the Expo client app.

If you know that you'll eventually need to include your own native code, Expo is still a good way to get started. In that case you'll need to "eject" eventually to create your own native builds. If you do eject, the "React Native CLI Quickstart" instructions will be required to continue working on your project.

Expo CLI configures your project to use the most recent React Native version that is supported by the Expo client app. The Expo client app usually gains support for a given React Native version about a week after the React Native version is released as stable. You can check this document to find out what versions are supported.

If you're integrating React Native into an existing project, you'll want to skip Expo CLI and go directly to setting up the native build environment. Select "React Native CLI Quickstart" above for instructions on configuring a native build environment for React Native.