Expo FirebaseRecaptcha

A library that provides functionality to create reCAPTCHA verifiers using Firebase.

Deprecated: This module will no longer be available in SDK 48. Learn how to migrate to React Native Firebase.

expo-firebase-recaptcha provides a set of building blocks for creating a reCAPTCHA verifier and using that with your Firebase Phone authentication workflow.

Firebase phone authentication is impossible out of the box using the Firebase JS SDK. This is because an Application Verifier object (reCAPTCHA) is needed as an additional security measure to verify that the user is real and not a bot.

Platform Compatibility

Installation

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Additionally, you'll also need to install the webview using npx expo install react-native-webview.

Usage

Additional configuration for iOS

expo-firebase-recaptcha uses native Firebase libraries on iOS that require additional configuration using the expo-build-properties config plugin. Install the plugin and apply the following configuration to your Expo config file.

Example app.json with config plugin

{
  "expo": {
    "plugins": [
      [
        "expo-build-properties",
        {
          "ios": {
            "useFrameworks": "static"
          }
        }
      ]
    ]
  }
}

With React Native Firebase

If you are using expo-firebase-recaptcha with React Native Firebase, you'll have to install the native SDK using the npx expo install command:

This will ensure that the @react-native-firebase/app dependency version is compatible with the Expo SDK version your project uses.

Also, make sure that you have React Native Firebase set up correctly in your project. For more information on how to configure it, see using the native Firebase SDK.

Basic usage

To get started, read the official Firebase phone-auth guide and ignore all steps that cover the reCAPTCHA configuration.

Instead of using the standard firebase.auth.RecaptchaVerifier class, we will be using our own verifier which creates a reCAPTCHA widget inside a web-browser.

Add the <FirebaseRecaptchaVerifierModal> component to your screen and store its ref for later use. Also pass in the Firebase web configuration using the firebaseConfig prop.

Optionally you can turn on experimental invisible reCAPTCHA using attemptInvisibleVerification. This feature is experimental and attempts to complete the verification process without showing any UI to the user. When invisible verification fails, the full reCATPCHA challenge UI is shown. The Google terms for invisible reCAPTCHA apply - use <FirebaseRecaptchaBanner> to show the Google terms when using invisible reCAPTCHA.

<FirebaseRecaptchaVerifierModal
  ref={/* store ref for later use */}
  firebaseConfig={/* firebase web config */}
  attemptInvisibleVerification={true | false /* experimental */}
/>

Pass in the recaptchaVerifier ref to verifyPhoneNumber. This will automatically show the reCAPTCHA modal when calling verifyPhoneNumber.

const phoneProvider = new firebase.auth.PhoneAuthProvider();
const verificationId = await phoneProvider.verifyPhoneNumber('+0123456789', recaptchaVerifierRef);

You should now receive an SMS message on your phone. Create a text-input field and let the user enter the verification code. The verificationId and the verificationCode can now be used to create a phone auth credential. Use that to sign in to firebase using signInWithCredential.

const credential = firebase.auth.PhoneAuthProvider.credential(verificationId, verificationCode);
const authResult = await firebase.auth().signInWithCredential(credential);

Phone authentication example

The examples below assumes that you are using firebase@9.x.x JS SDK.

import * as React from 'react';
import {
  Text,
  View,
  TextInput,
  Button,
  StyleSheet,
  TouchableOpacity,
  Platform,
} from 'react-native';
import { FirebaseRecaptchaVerifierModal, FirebaseRecaptchaBanner } from 'expo-firebase-recaptcha';
import { initializeApp, getApp } from 'firebase/app';
import { getAuth, PhoneAuthProvider, signInWithCredential } from 'firebase/auth';

// Initialize Firebase JS SDK >=9.x.x
// https://firebase.google.com/docs/web/setup
/*try {
  initializeApp({
    ...
  });
} catch (err) {
  // ignore app already initialized error in snack
}*/

// Firebase references
const app = getApp();
const auth = getAuth(app);

// Double-check that we can run the example
if (!app?.options || Platform.OS === 'web') {
  throw new Error(
    'This example only works on Android or iOS, and requires a valid Firebase config.'
  );
}

export default function App() {
  // Ref or state management hooks
  const recaptchaVerifier = React.useRef(null);
  const [phoneNumber, setPhoneNumber] = React.useState();
  const [verificationId, setVerificationId] = React.useState();
  const [verificationCode, setVerificationCode] = React.useState();

  const firebaseConfig = app ? app.options : undefined;
  const [message, showMessage] = React.useState();
  const attemptInvisibleVerification = false;

  return (
    <View style={{ padding: 20, marginTop: 50 }}>
      <FirebaseRecaptchaVerifierModal
        ref={recaptchaVerifier}
        firebaseConfig={firebaseConfig}
        // attemptInvisibleVerification
      />
      <Text style={{ marginTop: 20 }}>Enter phone number</Text>
      <TextInput
        style={{ marginVertical: 10, fontSize: 17 }}
        placeholder="+1 999 999 9999"
        autoFocus
        autoCompleteType="tel"
        keyboardType="phone-pad"
        textContentType="telephoneNumber"
        onChangeText={setPhoneNumber}
      />
      <Button
        title="Send Verification Code"
        disabled={!phoneNumber}
        onPress={async () => {
          // The FirebaseRecaptchaVerifierModal ref implements the
          // FirebaseAuthApplicationVerifier interface and can be
          // passed directly to `verifyPhoneNumber`.
          try {
            const phoneProvider = new PhoneAuthProvider(auth);
            const verificationId = await phoneProvider.verifyPhoneNumber(
              phoneNumber,
              recaptchaVerifier.current
            );
            setVerificationId(verificationId);
            showMessage({
              text: 'Verification code has been sent to your phone.',
            });
          } catch (err) {
            showMessage({ text: `Error: ${err.message}`, color: 'red' });
          }
        }}
      />
      <Text style={{ marginTop: 20 }}>Enter Verification code</Text>
      <TextInput
        style={{ marginVertical: 10, fontSize: 17 }}
        editable={!!verificationId}
        placeholder="123456"
        onChangeText={setVerificationCode}
      />
      <Button
        title="Confirm Verification Code"
        disabled={!verificationId}
        onPress={async () => {
          try {
            const credential = PhoneAuthProvider.credential(verificationId, verificationCode);
            await signInWithCredential(auth, credential);
            showMessage({ text: 'Phone authentication successful 👍' });
          } catch (err) {
            showMessage({ text: `Error: ${err.message}`, color: 'red' });
          }
        }}
      />
      {message ? (
        <TouchableOpacity
          style={[
            StyleSheet.absoluteFill,
            { backgroundColor: 0xffffffee, justifyContent: 'center' },
          ]}
          onPress={() => showMessage(undefined)}>
          <Text
            style={{
              color: message.color || 'blue',
              fontSize: 17,
              textAlign: 'center',
              margin: 20,
            }}>
            {message.text}
          </Text>
        </TouchableOpacity>
      ) : undefined}
      {attemptInvisibleVerification && <FirebaseRecaptchaBanner />}
    </View>
  );
}

import * as React from 'react';
import { Text, View, StyleSheet, TextInput, Button, Alert, ActivityIndicator } from 'react-native';
import * as FirebaseRecaptcha from 'expo-firebase-recaptcha';
import { initializeApp, getApp } from 'firebase/app';
import { getAuth, PhoneAuthProvider, signInWithCredential } from 'firebase/auth';

// Add your Firebase >=9.x.x config here
// https://firebase.google.com/docs/web/setup
const firebaseConfig = {
  /*apiKey: "api-key",
  authDomain: "project-id.firebaseapp.com",
  databaseURL: "https://project-id.firebaseio.com",
  projectId: "project-id",
  storageBucket: "project-id.appspot.com",
  messagingSenderId: "sender-id",
  appId: "app-id",
  measurementId: "G-measurement-id",*/
};

try {
  if (FIREBASE_CONFIG.apiKey) {
    initializeApp(FIREBASE_CONFIG);
  }
} catch (err) {
  // ignore app already initialized error on snack
}

// Firebase references
const app = getApp();
const auth = getAuth(app);

export default function PhoneAuthScreen() {
  const recaptchaVerifier = React.useRef(null);
  const verificationCodeTextInput = React.useRef(null);
  const [phoneNumber, setPhoneNumber] = React.useState('');
  const [verificationId, setVerificationId] = React.useState('');
  const [verifyError, setVerifyError] = React.useState();
  const [verifyInProgress, setVerifyInProgress] = React.useState(false);
  const [verificationCode, setVerificationCode] = React.useState('');
  const [confirmError, setConfirmError] = React.useState();
  const [confirmInProgress, setConfirmInProgress] = React.useState(false);
  const isConfigValid = !!FIREBASE_CONFIG.apiKey;

  return (
    <View style={styles.container}>
      <View style={styles.content}>
        <FirebaseRecaptcha.FirebaseRecaptchaVerifierModal
          ref={recaptchaVerifier}
          firebaseConfig={FIREBASE_CONFIG}
        />
        <Text style={styles.title}>Firebase Phone Auth</Text>
        <Text style={styles.subtitle}>using expo-firebase-recaptcha</Text>
        <Text style={styles.text}>Enter phone number</Text>
        <TextInput
          style={styles.textInput}
          autoFocus={isConfigValid}
          autoCompleteType="tel"
          keyboardType="phone-pad"
          textContentType="telephoneNumber"
          placeholder="+1 999 999 9999"
          editable={!verificationId}
          onChangeText={setPhoneNumber}
        />
        <Button
          title={`${verificationId ? 'Resend' : 'Send'} Verification Code`}
          disabled={!phoneNumber}
          onPress={async () => {
            const phoneProvider = new PhoneAuthProvider(auth);
            try {
              setVerifyError(undefined);
              setVerifyInProgress(true);
              setVerificationId('');
              const verificationId = await phoneProvider.verifyPhoneNumber(
                phoneNumber,
                recaptchaVerifier.current
              );
              setVerifyInProgress(false);
              setVerificationId(verificationId);
              verificationCodeTextInput.current?.focus();
            } catch (err) {
              setVerifyError(err);
              setVerifyInProgress(false);
            }
          }}
        />
        {verifyError && <Text style={styles.error}>{`Error: ${verifyError.message}`}</Text>}
        {verifyInProgress && <ActivityIndicator style={styles.loader} />}
        {verificationId ? (
          <Text style={styles.success}>A verification code has been sent to your phone</Text>
        ) : undefined}
        <Text style={styles.text}>Enter verification code</Text>
        <TextInput
          ref={verificationCodeTextInput}
          style={styles.textInput}
          editable={!!verificationId}
          placeholder="123456"
          onChangeText={setVerificationCode}
        />
        <Button
          title="Confirm Verification Code"
          disabled={!verificationCode}
          onPress={async () => {
            try {
              setConfirmError(undefined);
              setConfirmInProgress(true);
              const credential = PhoneAuthProvider.credential(verificationId, verificationCode);
              const authResult = await signInWithCredential(auth, credential);
              setConfirmInProgress(false);
              setVerificationId('');
              setVerificationCode('');
              verificationCodeTextInput.current?.clear();
              Alert.alert('Phone authentication successful!');
            } catch (err) {
              setConfirmError(err);
              setConfirmInProgress(false);
            }
          }}
        />
        {confirmError && <Text style={styles.error}>{`Error: ${confirmError.message}`}</Text>}
        {confirmInProgress && <ActivityIndicator style={styles.loader} />}
      </View>
      {!isConfigValid && (
        <View style={styles.overlay} pointerEvents="none">
          <Text style={styles.overlayText}>
            To get started, set a valid firebaseConfig in App.js.
          </Text>
        </View>
      )}
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    padding: 20,
  },
  content: {
    marginTop: 50,
  },
  title: {
    marginBottom: 2,
    fontSize: 29,
    fontWeight: 'bold',
  },
  subtitle: {
    marginBottom: 10,
    opacity: 0.35,
    fontWeight: 'bold',
  },
  text: {
    marginTop: 30,
    marginBottom: 4,
  },
  textInput: {
    marginBottom: 8,
    fontSize: 17,
    fontWeight: 'bold',
  },
  error: {
    marginTop: 10,
    fontWeight: 'bold',
    color: 'red',
  },
  success: {
    marginTop: 10,
    fontWeight: 'bold',
    color: 'blue',
  },
  loader: {
    marginTop: 10,
  },
  overlay: {
    ...StyleSheet.absoluteFillObject,
    backgroundColor: '#FFFFFFC0',
    justifyContent: 'center',
    alignItems: 'center',
  },
  overlayText: {
    fontWeight: 'bold',
  },
});

Customizing the appearance

<FirebaseRecaptchaVerifierModal> has limited customization options. You cannot change its appearance, but you can change the title and the cancel-label.

<FirebaseRecaptchaVerifierModal
  ref={...}
  firebaseConfig={...}
  title='Prove you are human!'
  cancelLabel='Close'
/>

If you want a custom look and feel, then create your own <Modal> or display the <FirebaseRecaptcha> component inline in your screen. Make sure to reserve enough space for the widget as it can not only display the compact "I'm not a robot" UI but also the full verification UI requiring users to select images.

import { FirebaseRecaptcha, FirebaseRecaptchaVerifier } from 'expo-firebase-recaptcha';

function CustomPhoneAuthScreen () {
  const [recaptchaToken, setRecaptchaToken] = React.useState('');

  async function onPressSendVerificationCode() {

    // Create an application verifier from the reCAPTCHA token
    if (!recaptchaToken) return;
    const applicationVerifier = new FirebaseRecaptchaVerifier(recaptchaToken);

    // Start phone authentication
    const phoneProvider = new PhoneAuthProvider();
    const verificationId = await phoneProvider.verifyPhoneNumber(
      '+0123456789',
      applicationVerifier
    );
  };

  return (
    <FirebaseRecaptcha
      style={...}
      firebaseConfig={...}

      // Store the reCAPTCHA token when it has been verified
      onVerify={token => setRecaptchaToken(token)}
      />
  );
}

API

import {
  FirebaseRecaptcha,
  FirebaseRecaptchaBanner,
  FirebaseRecaptchaVerifier,
  FirebaseRecaptchaVerifierModal,
  FirebaseAuthApplicationVerifier,
} from 'expo-firebase-recaptcha';

<FirebaseRecaptchaVerifierModal>

Modal screen that is automatically shown and displays a reCAPTCHA widget. The ref to the component implements the FirebaseAuthApplicationVerifier interface and can be used directly in the verifyPhoneNumber function.

Props

• firebaseConfig (IFirebaseOptions) -- Firebase web configuration.
• firebaseVersion (string) -- Optional version of the Firebase JavaScript SDK to load in the web-view. You can use this to load a custom or newer version. For example version="7.9.0".
• attemptInvisibleVerification (boolean) -- Attempts to verify without showing the reCAPTCHA workflow. The default is false. (Google terms apply - use FirebaseRecaptchaBanner to show the Google terms and policy).
• appVerificationDisabledForTesting (boolean) -- When set, disables app verification for the purpose of testing phone authentication. When this prop is true, a mock reCAPTCHA is rendered. This is useful for manual testing during development or for automated integration tests. See Firebase Phone Auth for more info.
• languageCode (string) -- Language to display the reCAPTCHA challenge in. For a list of possible languages, see reCAPTCHA Language Codes.
• title (string) -- Title that is displayed on the top of the modal. The default is "reCAPTCHA".
• cancelLabel (string) -- Label of the cancel button. The default is "Cancel".

<FirebaseRecaptcha>

The reCAPTCHA v3 widget displayed inside a web-view.

Props

• firebaseConfig (IFirebaseOptions) -- Firebase web configuration.
• firebaseVersion (string) -- Optional version of the Firebase JavaScript SDK to load in the web-view. You can use this to load a custom or newer version. For example version="7.9.0".
• appVerificationDisabledForTesting (boolean) -- When set, disables app verification for the purpose of testing phone authentication. When this prop is true, a mock reCAPTCHA is rendered. This is useful for manual testing during development or for automated integration tests. See Firebase Phone Auth for more info.
• languageCode (string) -- Language to display the reCAPTCHA challenge in. For a list of possible languages, see reCAPTCHA Language Codes.
• onLoad (function) -- A callback that is invoked when the widget has been loaded.
• onError (function) -- A callback that is invoked when the widget failed to load.
• onVerify (function) -- A callback that is invoked when reCAPTCHA has verified that the user is not a bot. The callback is provided with the reCAPTCHA token string. Example onVerify={token => setRecaptchaToken(token)}.
• onFullChallenge (function) -- A callback that is invoked when reCAPTCHA shows the full challenge experience.
• invisible (boolean) -- When true renders an invisible reCAPTCHA widget. The widget can then be triggered to verify invisibly by setting the verify prop to true.
• verify (boolean) -- Use this in combination with invisible=true so start the verification process.

<FirebaseRecaptchaBanner>

Renders a banner referring to the Google Privacy Policy and Terms or Service. You can use this component to show the Google terms when using invisible reCAPTCHA.

Props

• textStyle (object) -- Style used for the reCAPTCHA banner text.
• linkStyle (object) -- Style used for the privacy and terms links text.

Example

<FirebaseRecaptchaBanner
  textStyle={{ fontSize: 14, opacity: 1 }}
  linkStyle={{ fontWeight: 'bold' }}
/>

FirebaseAuthApplicationVerifier

Interface describing a domain verification and abuse prevention verifier.

interface FirebaseAuthApplicationVerifier {
  readonly type: string; // Identifies the type of application verifier (e.g. "recaptcha").
  verify(): Promise<string>; // Returns a token that can be used to assert the validity of a request.
}

FirebaseRecaptchaVerifier

A helper class implementing the FirebaseAuthApplicationVerifier interface, which can be used when creating a customized reCAPTCHA workflow. The class takes a single string argument in the constructor which should be a valid reCAPTCHA token.

Example

const applicationVerifier = new FirebaseRecaptchaVerifier(recaptchaToken);

const phoneProvider = new PhoneAuthProvider();
const verificationId = await phoneProvider.verifyPhoneNumber('+0123456789', applicationVerifier);