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

→ npx 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';

Interfaces

`AndroidManifest`

AndroidManifest Properties

Name	Type	Description
versionCode	`number`	Deprecated. Use `expo-application`'s `Application.nativeBuildVersion`. 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.

`IOSManifest`

IOSManifest Properties

Name	Type	Description
buildNumber	`null \| string`	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.
model	`null \| string`	Deprecated. Moved to `expo-device` as `Device.modelName`. The human-readable model name of this device, e.g. `"iPhone 7 Plus"` if it can be determined, otherwise will be `null`.
platform	`string`	Deprecated. Use `expo-device`'s `Device.modelId`. The Apple internal model identifier for this device, e.g. `iPhone1,1`.
systemVersion	`string`	Deprecated. Use `expo-device`'s `Device.osVersion`. The version of iOS running on this device, e.g. `10.3`.
userInterfaceIdiom	`UserInterfaceIdiom`	Deprecated. Use `expo-device`'s `Device.getDeviceTypeAsync()`. The user interface idiom of this device, i.e. whether the app is running on an iPhone or an iPad.

`ManifestAsset`

ManifestAsset Properties

Name	Type	Description
url	`string`	-

`NativeConstants`

NativeConstants Methods

`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.

Returns

Promise<null | string>

NativeConstants Properties

Name	Type	Description
appOwnership	`null \| 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`.
debugMode	`boolean`	-
deviceName (optional)	`string`	A human-readable name for the device type.
deviceYearClass	`null \| number`	Deprecated. Moved to `expo-device` as `Device.deviceYearClass`. The device year class of this device.
executionEnvironment	`ExecutionEnvironment`	-
experienceUrl	`string`	-
expoConfig	`null \| ExpoConfig`	The standard Expo config object defined in `app.config.js` files. For both classic and new manifests.
expoRuntimeVersion	`null \| string`	-
expoVersion	`null \| string`	The version string of the Expo Go app currently running. Returns `null` in bare workflow and web.
installationId	`string`	Deprecated. `Constants.installationId` is deprecated in favor of generating your own ID and storing it. An identifier that is unique to this particular device and whose lifetime is at least as long as the installation of the app.
intentUri (optional)	`string`	-
isDetached (optional)	`boolean`	-
isDevice	`boolean`	Deprecated. Use `expo-device`'s `Device.isDevice`. `true` if the app is running on a device, `false` if running in a simulator or emulator.
isHeadless	`boolean`	-
linkingUri	`string`	-
manifest	`null \| AppManifest`	Classic manifest for Expo apps using classic updates. Returns `null` in bare workflow and when `manifest2` is non-null.
manifest2	`null \| Manifest`	New manifest for Expo apps using modern Expo Updates. Returns `null` in bare workflow and when `manifest` is non-null.
nativeAppVersion	`null \| string`	Deprecated. Use `expo-application`'s `Application.nativeApplicationVersion`. 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.
nativeBuildVersion	`null \| string`	Deprecated. Use `expo-application`'s `Application.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.
platform (optional)	`PlatformManifest`	-
sessionId	`string`	A string that is unique to the current session of your app. It is different across apps and across multiple launches of the same app.
statusBarHeight	`number`	The default status bar height for the device. Does not factor in changes when location tracking is in use or a phone call is active.
systemFonts	`string[]`	A list of the system font names available on the current device.
systemVersion (optional)	`number`	-

`PlatformManifest`

PlatformManifest Properties

Name	Type	Description
android (optional)	`AndroidManifest`	-
detach (optional)	`{ scheme: string }`	-
developer (optional)	`string`	-
hostUri (optional)	`string`	-
ios (optional)	`IOSManifest`	-
logUrl (optional)	`string`	-
scheme (optional)	`string`	-
web (optional)	`WebManifest`	-

Types

`AppManifest`

Represents an intersection of all possible Config types.

Acceptable values are: ExpoClientConfig, ExpoGoConfig, EASConfig, ClientScopingConfig, Record<string, any>.

`ClientScopingConfig`

Name	Type	Description
scopeKey (optional)	`string`	An opaque unique string for scoping client-side data to this project. This value will not change when a project is transferred between accounts or renamed.

`EASConfig`

Name	Type	Description
projectId (optional)	`string`	The ID for this project if it's using EAS. UUID. This value will not change when a project is transferred between accounts or renamed.

`ExpoClientConfig`

ExpoConfig extended by:

Name	Type	Description
bundleUrl	`string`	-
currentFullName (optional)	`string`	The Expo account name and slug used for display purposes. Formatted like `@username/slug`. When unauthenticated, the username is `@anonymous`. For published projects, this value may change when a project is transferred between accounts or renamed.
hostUri (optional)	`string`	-
id (optional)	`string`	Deprecated. Prefer `projectId` or `originalFullName` instead for identification and `scopeKey` for scoping due to immutability. The Expo account name and slug for this project.
originalFullName (optional)	`string`	The original Expo account name and slug for this project. Formatted like `@username/slug`. When unauthenticated, the username is `@anonymous`. For published projects, this value will not change when a project is transferred between accounts or renamed.
publishedTime (optional)	`string`	-
releaseChannel (optional)	`string`	-
releaseId (optional)	`string`	Published apps only.
revisionId (optional)	`string`	-

`ExpoGoConfig`

Name	Type	Description
debuggerHost (optional)	`string`	-
developer (optional)	`{ tool: string }`	-
logUrl (optional)	`string`	-
mainModuleName (optional)	`string`	-
packagerOpts (optional)	`ExpoGoPackagerOpts`	-

`ExpoGoPackagerOpts`

Name	Type	Description
dev (optional)	`boolean`	-
hostType (optional)	`string`	-
lanType (optional)	`string`	-
minify (optional)	`boolean`	-
strict (optional)	`boolean`	-
urlRandomness (optional)	`string`	-
urlType (optional)	`string`	-
key (index signature)	`string`	-

`Manifest`

A modern manifest.

Name	Type	Description
assets	`ManifestAsset[]`	-
createdAt	`string`	-
extra (optional)	`ManifestExtra`	-
id	`string`	-
launchAsset	`ManifestAsset`	-
metadata	`object`	-
runtimeVersion	`string`	-