expo-constants

Open Beta Documentation Amazon offers this technical documentation as part of a pre-release, open beta. The features described might change as Amazon receives feedback and iterates on the features. For the most current feature information, see the latest Release Notes.

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

Installation

Add the JavaScript library dependency in the package.json file. Select the tab for your React Native version.

React Native 0.72
React Native 0.83

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 dependencies: {
     ...
     "@amazon-devices/expo-constants": "~2.0.0",
     "expo": "~50.0.0",
     ...
 }

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 dependencies: {
     ...
     "@amazon-devices/expo-constants": "~3.0.0",
     "expo": "~50.0.0",
     ...
 }

Reinstall dependencies using npm install command.

Examples

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import React from 'react';
import Constants from '@amazon-devices/expo-constants';
import {StyleSheet, Text, View} from 'react-native';

export const App = () => {
  return (
    <View style={styles.container}>
      <Text style={styles.text}>
        isHeadless: {String(Constants.isHeadless)}
      </Text>
      <Text style={styles.text}>
        statusBarHeight: {Constants.statusBarHeight}
      </Text>
      <Text style={styles.text}>
        systemFonts: {Constants.systemFonts.join(', ')}
      </Text>
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'white',
    justifyContent: 'center',
    alignItems: 'center',
  },
  text: {
    fontSize: 30,
    color: 'black',
  },
});

API reference

Check out the dedicated documentation page for info about this library, API reference and more: Official Expo documentation for expo-constants.

Implementation details

Currently, all values are mocks. Don't depend on any of the constants inside this package.

Supported versions

NPM package version	Vega SDK version	Vega OS version	React Native version
2.0.1758683737	0.23 and earlier	`OS 1.1 (1401010009820)` and earlier	0.72
3.0.1+15.2.0	0.24	`OS 1.2 (2101020054720)`	0.72, 0.83

Additional resources

For information on additional libraries, see Supported Third-Party Libraries and Services.

Last updated: Aug 03, 2026