expo-local-authentication

What is expo-local-authentication?

The expo-local-authentication package provides an API for authenticating users using biometric methods such as fingerprint, facial recognition, or iris recognition on devices that support these features. It is part of the Expo ecosystem, which is designed to work seamlessly with React Native applications.

What are expo-local-authentication's main functionalities?

Check if hardware supports local authentication

This feature allows you to check if the device has the necessary hardware to support local authentication methods like fingerprint or facial recognition.

import * as LocalAuthentication from 'expo-local-authentication';

async function checkHardware() {
  const hasHardware = await LocalAuthentication.hasHardwareAsync();
  console.log('Hardware available:', hasHardware);
}

Check if biometrics are enrolled

This feature checks if the user has enrolled any biometric data (e.g., fingerprints or face) on their device.

import * as LocalAuthentication from 'expo-local-authentication';

async function checkBiometrics() {
  const isEnrolled = await LocalAuthentication.isEnrolledAsync();
  console.log('Biometrics enrolled:', isEnrolled);
}

Authenticate using biometrics

This feature initiates the biometric authentication process, prompting the user to authenticate using their enrolled biometric data.

import * as LocalAuthentication from 'expo-local-authentication';

async function authenticate() {
  const result = await LocalAuthentication.authenticateAsync();
  console.log('Authentication result:', result);
}

Other packages similar to expo-local-authentication

react-native-touch-id

The react-native-touch-id package provides similar functionality for biometric authentication, focusing primarily on Touch ID and Face ID for iOS devices. It offers a straightforward API for integrating biometric authentication into React Native apps, but it may require additional setup for Android support compared to expo-local-authentication.

react-native-fingerprint-scanner

This package provides a more comprehensive solution for fingerprint scanning across both iOS and Android platforms. It offers more detailed configuration options and error handling compared to expo-local-authentication, but it may require more manual setup and linking in a React Native project.

README

Provides an API for FaceID and TouchID (iOS) or the Fingerprint API (Android) to authenticate the user with a face or fingerprint scan.

API documentation

• Documentation for the latest stable release
• Documentation for the main branch

Installation in managed Expo projects

For managed Expo projects, please follow the installation instructions in the API documentation for the latest stable release.

Installation in bare React Native projects

For bare React Native projects, you must ensure that you have installed and configured the expo package before continuing.

Add the package to your npm dependencies

npx expo install expo-local-authentication

Configure for Android

No additional set up necessary.

This module requires permissions to access the biometric data for authentication purposes. The USE_BIOMETRIC and USE_FINGERPRINT permissions are automatically added.

<!-- Added permissions -->
<uses-permission android:name="android.permission.USE_BIOMETRIC" />
<uses-permission android:name="android.permission.USE_FINGERPRINT" />

Configure for iOS

Run npx pod-install after installing the npm package.

Add NSFaceIDUsageDescription to your Info.plist:

<key>NSFaceIDUsageDescription</key>
<string>Allow $(PRODUCT_NAME) to use FaceID</string>

Contributing

Contributions are very welcome! Please refer to guidelines described in the contributing guide.