npx expo install react-native-auth0

npm install react-native-auth0
npx pod-install  # iOS only

AUTH0_DOMAIN=your-tenant.auth0.com
AUTH0_CLIENT_ID=your-client-id

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleTypeRole</key>
    <string>None</string>
    <key>CFBundleURLName</key>
    <string>auth0</string>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>$(PRODUCT_BUNDLE_IDENTIFIER).auth0</string>
    </array>
  </dict>
</array>

<activity
    android:name="com.auth0.android.provider.RedirectActivity"
    android:exported="true">
    <intent-filter>
        <action android:name="android.intent.action.VIEW" />
        <category android:name="android.intent.category.DEFAULT" />
        <category android:name="android.intent.category.BROWSABLE" />
        <data
            android:host="YOUR_AUTH0_DOMAIN"
            android:pathPrefix="/android/${applicationId}/callback"
            android:scheme="${applicationId}" />
    </intent-filter>
</activity>

{
  "expo": {
    "scheme": "your-app-scheme",
    "ios": {
      "bundleIdentifier": "com.yourcompany.yourapp"
    },
    "android": {
      "package": "com.yourcompany.yourapp"
    }
  }
}

import React from 'react';
import { Auth0Provider } from 'react-native-auth0';
import App from './App';

export default function Root() {
  return (
    <Auth0Provider
      domain={process.env.AUTH0_DOMAIN}
      clientId={process.env.AUTH0_CLIENT_ID}
    >
      <App />
    </Auth0Provider>
  );
}

import React from 'react';
import { View, Button, Text, ActivityIndicator } from 'react-native';
import { useAuth0 } from 'react-native-auth0';

export default function App() {
  const { user, authorize, clearSession, isLoading } = useAuth0();

  const login = async () => {
    try {
      await authorize({
        scope: 'openid profile email'
      });
    } catch (error) {
      console.error('Login error:', error);
    }
  };

  const logout = async () => {
    try {
      await clearSession();
    } catch (error) {
      console.error('Logout error:', error);
    }
  };

  if (isLoading) {
    return <ActivityIndicator />;
  }

  return (
    <View>
      {user ? (
        <>
          <Text>Welcome, {user.name}!</Text>
          <Text>{user.email}</Text>
          <Button title="Logout" onPress={logout} />
        </>
      ) : (
        <Button title="Login" onPress={login} />
      )}
    </View>
  );
}

npx expo start

npx react-native run-ios
# or
npx react-native run-android