Constants

expo-constants provides system information that remains constant throughout the lifetime of your app's install.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web

Installation

Terminal

→ expo install expo-constants

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

API

import Constants from 'expo-constants';

Properties

`Constants.appOwnership`

Returns expo, standalone, or guest. This property only applies to the managed workflow and classic builds; for apps built with EAS Build and in bare workflow, the result is always null.

expo: The experience is running inside of the Expo Go app.
standalone: It is a standalone app.
guest: It has been opened through a link from a standalone app.

`Constants.deviceName`

A human-readable name for the device type.

`Constants.expoVersion`

The version string of the Expo Go app currently running.

`Constants.getWebViewUserAgentAsync()`

Gets the user agent string which would be included in requests sent by a web view running on this device. This is probably not the same user agent you might be providing in your JS fetch requests.

`Constants.installationId`

⚠️
This property is deprecated and will be removed in SDK 44. Please implement it on your own using expo-application's androidId on Android and a storage API such as expo-secure-store on iOS and localStorage on Web.

An identifier that is unique to this particular device and whose lifetime is at least as long as the installation of the app.

`Constants.isDevice`

true if the app is running on a device, false if running in a simulator or emulator.

`Constants.nativeAppVersion`

The Info.plist value for CFBundleShortVersionString on iOS and the version name set by version in app.json on Android at the time the native app was built.

`Constants.nativeBuildVersion`

The Info.plist value for CFBundleVersion on iOS (set with ios.buildNumber value in app.json in a standalone app) and the version code set by android.versionCode in app.json on Android at the time the native app was built.

`Constants.platform`

ios
- buildNumber
  The build number specified in the embedded Info.plist value for CFBundleVersion in this app. In a standalone app, you can set this with the ios.buildNumber value in app.json. This may differ from the value in Constants.manifest.ios.buildNumber because the manifest can be updated, whereas this value will never change for a given native binary. The value is set to null in case you run your app in Expo Go.
- platform
  The Apple internal model identifier for this device, e.g. iPhone1,1.
- model
The human-readable model name of this device, e.g. "iPhone 7 Plus" if it can be determined, otherwise will be null.
- userInterfaceIdiom
The user interface idiom of this device, i.e. whether the app is running on an iPhone or an iPad. Current supported values are handset and tablet. Apple TV and CarPlay will show up as unsupported.
- systemVersion
The version of iOS running on this device, e.g. 10.3.
android
- versionCode
  The version code set by android.versionCode in app.json. The value is set to null in case you run your app in Expo Go.

Expo