Expo Docs

Hey friend! We are co-hosting a conference with Software Mansion, learn more.

Configuration with app.json

app.json is your go-to place for configuring parts of your app that don't belong in code. It is located at the root of your project next to your package.json. It looks something like this:
{
  "expo": {
    "name": "My app",
    "slug": "my-app",
    "sdkVersion": "UNVERSIONED",
    "privacy": "public"
  }
}
app.json was previous referred to as exp.json, but for consistency with Create React Native App it has been consolidated under one file. If you are converting your app from using exp.json to app.json, all you need to do is add an "expo" key at the root of app.json, as the parent of all other keys.
Most configuration from app.json is accessible at runtime from your JavaScript code via Expo.Constants.manifest. Sensitive information such as secret keys are removed. See the "extra" key below for information about how to pass arbitrary configuration data to your app.
The following is a list of properties that are available for you under the "expo" key in app.json:

Required. The name of your app as it appears both within Expo and on your home screen as a standalone app.

A short description of what your app is and why it is great.

Required. The friendly url name for publishing. eg: my-app-name will refer to the expo.io/@your-username/my-app-name project.

Either public or unlisted. If not provided, defaults to unlisted. In the future private will be supported. unlisted hides the experience from search results. Valid values: public, unlisted

Required. The Expo sdkVersion to run the project on. This should line up with the version specified in your package.json.

Your app version, use whatever versioning scheme that you like.

Platforms that your project explicitly supports. If not specified, it defaults to ["ios", "android"].

If you would like to share the source code of your app on Github, enter the URL for the repository here and it will be linked to from your Expo project page.

Lock your app to a specific orientation with portrait or landscape. Defaults to no lock. Valid values: 'default', 'portrait', 'landscape'

On Android, this will determine the color of your app in the multitasker. Currently this is not used on iOS, but it may be used for other purposes in the future.
6 character long hex color string, eg: "#000000"

Local path or remote url to an image to use for your app's icon. We recommend that you use a 1024x1024 png file. This icon will appear on the home screen and within the Expo app.

DEPRECATED: Use splash instead.

By default, Expo looks for the application registered with the AppRegistry as main. If you would like to change this, you can specify the name in this property.

Adds a notification to your standalone app with refresh button and debug info.

Standalone Apps Only. URL scheme to link into your app. For example, if we set this to 'demo', then demo:// URLs would open your app when tapped. String beginning with a letter followed by any combination of letters, digits, "+", "." or "-"

The relative path to your main JavaScript file.

Any extra fields you want to pass to your experience. Values are accessible via Expo.Constants.manifest.extra (read more)

Used for all Facebook libraries. Set up your Facebook App ID at https://developers.facebook.com.

Used for native Facebook login.

Used for Facebook native login. Starts with 'fb' and followed by a string of digits, like 'fb1234567890'. You can find your scheme at https://developers.facebook.com/docs/facebook-login/ios in the 'Configuring Your info.plist' section.

Provide overrides by locale for System Dialog prompts like Permissions Boxes

An array of file glob strings which point to assets that will be bundled within your standalone app binary. Read more in the Offline Support guide

DEPRECATED. Use androidStatusBar instead.

Configuration for android statusbar.
{
  "androidStatusBar": {
    /* 
      Configure the statusbar icons to have light or dark color. 
      Valid values: "light-content", "dark-content".
    */
    "barStyle": STRING,

    /* 
      Configuration for android statusbar.
      6 character long hex color string, eg: "#000000" 
    */
    "backgroundColor": STRING
  }
}

Configuration for loading and splash screen for standalone apps.
{
  "splash": {
    /* 
      Color to fill the loading screen background
      6 character long hex color string, eg: "#000000" 
    */
    "backgroundColor": STRING,

    /* 
      Determines how the "image" will be displayed in the splash loading screen. 
      Must be one of "cover" or "contain", defaults to `contain`. 
      Valid values: "cover", "contain" 
    */
    "resizeMode": STRING,

    /* 
      Local path or remote url to an image.
      Will fill the background of the loading/splash screen. 
      Image size and aspect ratio are up to you. Must be a .png.
    */
    "image": STRING
  }
}

Configuration for remote (push) notifications.
{
  "notification": {
    /* 
      Local path or remote url to an image to use as the icon for push notifications. 
      96x96 png grayscale with transparency.
    */
    "icon": STRING,

    /* 
      Tint color for the push notification image when it appears in the notification tray.
      6 character long hex color string eg: "#000000" 
    */
    "color": STRING,

    /* 
      Show each push notification individually "default" or collapse into one "collapse".
      Valid values: "default", "collapse"
    */
    "androidMode": STRING,

    /* 
      If "androidMode" is set to "collapse", this title is used for the collapsed notification message. 
      eg: "#{unread_notifications} new interactions" 
    */
    "androidCollapsedTitle": STRING
  }
}

Configuration for scripts to run to hook into the publish process
{
  "hooks": {
    "postPublish": STRING
  }
}

Configuration for how and when the app should request OTA JavaScript updates
{
  "updates": {
    /* 
      If set to false, your standalone app will never download any code.
      And will only use code bundled locally on the device. 
      In that case, all updates to your app must be submitted through Apple review. 
      Defaults to true.

      Note that this will not work out of the box with ExpoKit projects.
    */
    "enabled": BOOLEAN,

    /* 
      By default, Expo will check for updates every time the app is loaded.
      Set this to `'ON_ERROR_RECOVERY'` to disable automatic checking unless recovering from an error.

      Must be one of `ON_LOAD` or `ON_ERROR_RECOVERY`. 
    */
    "checkAutomatically": STRING,

    /* 
      How long (in ms) to allow for fetching OTA updates before falling back to a cached version of the app. 

      Defaults to 30000 (30 sec). Must be between 0 and 300000 (5 minutes). 
    */
    "fallbackToCacheTimeout": NUMBER
  }
}

Standalone Apps Only. iOS standalone app specific configuration
{
  "ios": {
    /*
      The bundle identifier for your iOS standalone app. 
      You make it up, but it needs to be unique on the App Store. 

      stackoverflow.com/questions/11347470/what-does-bundle-identifier-mean-in-the-ios-project.

      iOS bundle identifier notation unique name for your app. 
      For example, host.exp.exponent, where exp.host is our domain 
      and Expo is our app.
    */
    "bundleIdentifier": STRING,

    /*
      Build number for your iOS standalone app. Must be a string 
      that matches Apple's format for CFBundleVersion.

      developer.apple.com/library/content/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html#//apple_ref/doc/uid/20001431-102364.
    */
    "buildNumber": STRING,

    /*
      Local path or remote URL to an image to use for your app's 
      icon on iOS. If specified, this overrides the top-level "icon" key. 

      Use a 1024x1024 icon which follows Apple's interface guidelines for icons, including color profile and transparency. 

      Expo will generate the other required sizes. 
      This icon will appear on the home screen and within the Expo app.
    */
    "icon": STRING,

    /*
      Merchant ID for use with Apple Pay in your standalone app.
    */
    "merchantId": STRING,

    /*
      URL to your app on the Apple App Store, if you have deployed it there. 
      This is used to link to your store page from your Expo project page if your app is public.
    */
    appStoreUrl: STRING,

    /*
      Whether your standalone iOS app supports tablet screen sizes. 
      Defaults to `false`.
    */
    "supportsTablet": BOOLEAN,

    /*
      If true, indicates that your standalone iOS app does not support handsets.
      Your app will only support tablets.
    */
    "isTabletOnly": BOOLEAN,

    /*
      Dictionary of arbitrary configuration to add to your standalone app's native Info.plist. Applied prior to all other Expo-specific configuration. 

      No other validation is performed, so use this at your own risk of rejection from the App Store.
    */
    "infoPlist": OBJECT,

    /*
      An array that contains Associated Domains for the standalone app.
    */
    "associatedDomains": ARRAY,

    /*
      A boolean indicating if the app uses iCloud Storage for DocumentPicker. 
      See DocumentPicker docs for details.
    */
    "usesIcloudStorage": BOOLEAN,

    "config": {
      /*
        Branch (https://branch.io/) key to hook up Branch linking services.
      */
      "branch": {
        /*
          Your Branch API key
        */
        "apiKey": STRING
      },

      /*
        Sets `ITSAppUsesNonExemptEncryption` in the standalone ipa's Info.plist to the given boolean value.
      */
      "usesNonExemptEncryption": BOOLEAN,

      /*
        Google Maps iOS SDK key for your standalone app. 

        developers.google.com/maps/documentation/ios-sdk/start
      */
      "googleMapsApiKey": STRING,

      /*
        Google Sign-In iOS SDK keys for your standalone app. 

        developers.google.com/identity/sign-in/ios/start-integrating
      */
      "googleSignIn": STRING,

      /*
        The reserved client ID URL scheme. 
        Can be found in GoogeService-Info.plist.
      */
      "reservedClientId": STRING
    },

    "splash": {
      /*
        Color to fill the loading screen background 6 character long hex color string, eg: "#000000"
      */
      "backgroundColor": STRING,

      /*
        Determines how the "image" will be displayed in the splash loading screen. 
        Must be one of "cover" or "contain", defaults to "contain".
        Valid values: "cover", "contain"
      */
      "resizeMode": STRING,

      /*
        Local path or remote url to an image to fill the background of the loading screen. 
        Image size and aspect ratio are up to you. 
        Must be a .png.
      */
      "image": STRING,

      /*
        Local path or remote url to an image to fill the background of the loading screen. 
        Image size and aspect ratio are up to you. 
        Must be a .png.
      */
      "tabletImage": STRING
    },

    "isRemoteJSEnabled": DEPRECATED,

    "loadJSInBackgroundExperimental": DEPRECATED,
  }
}

Standalone Apps Only. Android standalone app specific configuration
{
  "android": {
    /*
      The package name for your Android standalone app. 
      You make it up, but it needs to be unique on the Play Store. 

      stackoverflow.com/questions/6273892/android-package-name-convention

      Reverse DNS notation unique name for your app. 
      For example, host.exp.exponent, where exp.host is our domain and Expo is our app.
    */
    "package": STRING,

    /*
      Version number required by Google Play. 
      Increment by one for each release. 
      Must be an integer. 
      developer.android.com/studio/publish/versioning.html
    */
    "versionCode": NUMBER,

    /*
      Local path or remote url to an image to use for your app's icon on Android. 
      If specified, this overrides the top-level "icon" key. 

      We recommend that you use a 1024x1024 png file.
      Transparency is recommended for the Google Play Store. 
      This icon will appear on the home screen and within the Expo app.
    */
    "icon": STRING,

    /*
      Settings for an Adaptive Launcher Icon on Android.
      [https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive](https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive)
    */
    "adaptiveIcon": {
      /*
        Local path or remote url to an image to use for
        the foreground of your app's icon on Android.

        We recommend that you use a 1024x1024 png file,
        leaving at least the outer 1/6 transparent on each side.
        If specified, this overrides the top-level "icon" and the "android.icon" keys.
        This icon will appear on the home screen.
      */
      "foregroundImage": STRING,

      /*
        Color to use as the background for your app's Adaptive Icon on Android.
        Defaults to white (#FFFFFF).

        Has no effect if "foregroundImage" is not specified.
      */
      "backgroundColor": STRING,

      /*
        Local path or remote url to a background image for
        the background of your app's icon on Android.

        If specified, this overrides the "backgroundColor" key.
        Must have the same dimensions as "foregroundImage", and has no effect if
        "foregroundImage" is not specified.
      */
      "backgroundImage": STRING
    },

    /*
      URL to your app on the Google Play Store, if you have deployed it there. 
      This is used to link to your store page from your Expo project page if your app is public.
    */
    "playStoreUrl": STRING,

    /*
      List of additional permissions the standalone app will request upon installation.
      Along with the minimum necessary for an expo app to function.  

      Don't use "permissions" to use the default list.

      Set "permissions" to [] to use ONLY the following MINIMUM necessary permissions:
      
      •	receive data from Internet
      •	view network connections
      •	full network access
      •	change your audio settings
      •	draw over other apps
      •	prevent device from sleeping
      •	view network connections
      •	full network access
      •	change your audio settings
      •	draw over other apps
      •	prevent device from sleeping
      
      Note: these do not require privacy policy when uploading to Google Play Store.
      
    */
    "permissions": [
      "ACCESS_COARSE_LOCATION",
      "ACCESS_FINE_LOCATION",
      "CAMERA",
      "MANAGE_DOCUMENTS",
      "READ_CONTACTS",
      "READ_CALENDAR",
      "WRITE_CALENDAR",
      "READ_EXTERNAL_STORAGE",
      "READ_PHONE_STATE",
      "RECORD_AUDIO",
      "USE_FINGERPRINT",
      "VIBRATE",
      "WAKE_LOCK",
      "WRITE_EXTERNAL_STORAGE",
      "com.anddoes.launcher.permission.UPDATE_COUNT",
      "com.android.launcher.permission.INSTALL_SHORTCUT",
      "com.google.android.c2dm.permission.RECEIVE",
      "com.google.android.gms.permission.ACTIVITY_RECOGNITION",
      "com.google.android.providers.gsf.permission.READ_GSERVICES",
      "com.htc.launcher.permission.READ_SETTINGS",
      "com.htc.launcher.permission.UPDATE_SHORTCUT",
      "com.majeur.launcher.permission.UPDATE_BADGE",
      "com.sec.android.provider.badge.permission.READ",
      "com.sec.android.provider.badge.permission.WRITE",
      "com.sonyericsson.home.permission.BROADCAST_BADGE"
    ],

    "config": {
      /*
        Branch (https://branch.io/) key to hook up Branch linking services.
      */
      "branch": {
        /*
          Your Branch API key
        */
        "apiKey": STRING
      },

      /*
        Google Developers Fabric keys to hook up Crashlytics and other services.
        get.fabric.io/
      */
      "fabric": {
        /*
          Your Fabric API key
        */
        "apiKey": STRING,

        /*
          Your Fabric build secret
        */
        "buildSecret": STRING
      },

      /*
        Google Maps Android SDK key for your standalone app.
        developers.google.com/maps/documentation/android-api/signup
      */
      "googleMaps": {
        /*
          Your Google Maps Android SDK API key
        */
        "apiKey": STRING
      }

      /*
        Google Sign-In Android SDK keys for your standalone app.
        developers.google.com/identity/sign-in/android/start-integrating
      */
      "googleSignIn": {
        /*
          The Android API key. 
          Can be found in the credentials section of the developer console 
          or in "google-services.json"
        */
        "apiKey": STRING,

        /*
          The SHA-1 hash of the signing certificate used to build the apk without any separator `:`. 
          Can be found in "google-services.json". 
          developers.google.com/android/guides/client-auth
        */
        "certificateHash": STRING
      }
    },

    /*
      Configuration for loading and splash screen for standalone Android apps.
    */
    "splash": {
      /*
        Color to fill the loading screen background
        6 character long hex color string, eg: "#000000"
      */
      "backgroundColor": STRING,

      /*
        Determines how the "image" will be displayed in the splash loading screen. 
        Must be one of "cover" or "contain", defaults to "contain". 
        Valid values: "cover", "contain"
      */
      "resizeMode": STRING,

      /*
        Local path or remote url to an image to fill the background of the loading screen. 
        Image size and aspect ratio are up to you. 
        Must be a .png.
      */
      "ldpi": STRING,
      "mdpi": STRING,
      "hdpi": STRING,
      "xhdpi": STRING,
      "xxhdpi": STRING,
      "xxxhdpi": STRING
    },

    /*
      Configuration for setting custom intent filters in Android manifest.
      The following example demonstrates how to set up deep links. When
      the user taps a link matching *.myapp.io, they will be shown a
      dialog asking whether the link should be handled by your app or by
      the web browser.

      The data attribute may either be an object or an array of objects. The object may have the following keys to specify attributes of URLs matched by the filter:

      - scheme (string): the scheme of the URL, e.g. "https"
      - host (string): the host, e.g. "myapp.io"
      - port (string): the port, e.g. "3000"
      - path (string): an exact path for URLs that should be matched by the filter, e.g. "/records"
      - pathPattern (string): a regex for paths that should be matched by the filter, e.g. ".*"
      - pathPrefix (string): a prefix for paths that should be matched by the filter, e.g. "/records/" will match "/records/123"
      - mimeType (string): a mime type for URLs that should be matched by the filter

      See Android's documentation for more details on intent filter matching:

      developer.android.com/guide/components/intents-filters

      You may also use an intent filter to set your app as the default handler
      for links (without showing the user a dialog with options). To do so, you
      must set "autoVerify": true on the filter object below, and then
      configure your server to serve a JSON file verifying that you own the
      domain. See Android's documentation for details:

      developer.android.com/training/app-links
    */
    "intentFilters": [
      {
        "action": "VIEW",
        "data": {
          "scheme": "https",
          "host": "*.myapp.io"
        },
        "category": [
          "BROWSABLE",
          "DEFAULT"
        ]
      }
    ]
  }
}