The Expo SDK provides access to device and system functionality such as contacts, camera, and GPS location. You install modules from the Expo SDK using expo-cli with the expo install command:

You can import modules from it in your JavaScript code as follows:

import { Camera } from 'expo-camera';
import * as Contacts from 'expo-contacts';
import { Gyroscope } from 'expo-sensors';

This allows you to write Contacts.getContactsAsync() and read the contacts from the device, read the gyroscope sensor to detect device movement, or render a Camera view and take photos.

The easiest way to create a bare React Native app with support for the Expo SDK is npx create-react-native-app myapp. If you have an existing app that you would like to add Expo SDK packages to, read about integrating into existing apps.

Every quarter there is a new Expo SDK release that typically updates to the latest stable version of React Native and includes a variety of bugfixes, features and improvements to the Expo SDK.

Packages in the Expo SDK are intended to support the target React Native version for that SDK. Typically, they will not support older versions of React Native, but they may. When a new version of React Native is released, the latest versions of the Expo SDK packages are typically updated to support it; however, this may take weeks or more, depending on the extent of the changes in the release.