Integrating Face ID & Touch ID Authentication in React Native

import * as Keychain from 'react-native-keychain';

// Save credentials with biometric access

await Keychain.setGenericPassword('username', 'password', {
  accessControl: Keychain.ACCESS_CONTROL.BIOMETRY_ANY,
  accessible: Keychain.ACCESSIBLE.WHEN_UNLOCKED,
});

import * as Keychain from 'react-native-keychain';

async function authenticate() {
  try {
    const creds = await Keychain.getGenericPassword({
      authenticationPrompt: {
        title: 'Login with Face ID / Touch ID',
      },
    });

    if (creds) {
      console.log('Authenticated!', creds.username);
    } else {
      console.log('No credentials stored');
    }
  } catch (err) {
    console.error('Authentication failed', err);
  }
}

Not all devices have Face ID or Touch ID. Always provide fallbacks:
const supported = await Keychain.getSupportedBiometryType();

if (supported) {
  console.log('Supported biometric:', supported);
} else {
  console.log('Fallback to PIN/Password');
}

npm install react-native-biometrics

import ReactNativeBiometrics from 'react-native-biometrics';
const rnBiometrics = new ReactNativeBiometrics();

rnBiometrics.simplePrompt({ promptMessage: 'Confirm with Face ID / Touch ID' })
  .then(result => {
    if (result.success) {
      console.log('Biometric authentication success');
    } else {
      console.log('User cancelled');
    }
  });