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Build configuration process

In this guide, you will learn what happens when EAS CLI configures your project with eas build:configure (or eas build - which runs this same process if the project is not yet configured).
EAS CLI performs the following steps when configuring your project:

1. Ask you about the platform(s) to configure

If you only want to use EAS Build for a single platform, that's fine. If you change your mind, you can come back and configure the other later.
Terminal running eas build command with platform iOS and Android options available

The command will create an eas.json file in the root directory with the default configuration. It looks something like this:
  "build": {
    "development": {
      "developmentClient": true,
      "distribution": "internal"
    "preview": {
      "distribution": "internal"
    "production": {}
If you have a bare project, it will look a bit different.
This is your EAS Build configuration. It defines three build profiles named development, preview, and production (you can have multiple build profiles like production, debug, testing, etc.) for each platform. If you want to learn more about eas.json see the Configuration with eas.json page.

This step varies depending on the project type you have.

If you choose to configure the Android project, EAS CLI will update your Gradle project so we can build it on our servers. This step patches build.gradle and includes our custom signing configuration. The configuration itself is saved to a separate file: eas-build.gradle.
If you also choose to configure the iOS project, there are no additional steps.

If you haven't configured your app.json with android.package and/or ios.bundleIdentifier yet, EAS CLI will prompt you to specify them.
  • android.package will be used as the Android application id which is used to identify your app on the Google Play Store
  • ios.bundleIdentifier will be used to identify you app on the Apple App Store
Application identifier prompts in eas build:configure
In the example above, we defined exactly the same Android application id and iOS bundle identifier. However, they don't need to match.

That's all there is to configuring a project to be compatible with EAS Build. There is one final step — you'll be prompted to commit all the changes we made for you. You can choose to review them before committing, and you can either specify the git commit message or use a default message.
Application identifier prompts in eas build:configure