The Complete Guide to Biometric Authentication in React Native

In today's mobile-first world, users expect authentication to be both secure and effortless. Typing passwords every time an app is opened not only impacts the user experience but also introduces security risks if passwords are weak or reused. Biometric authentication solves this problem by allowing users to verify their identity using Fingerprint, Face ID, Touch ID, Iris Scanner, or even their device's PIN/Password.

If you're building a React Native application, @sbaiahmed1/react-native-biometrics is one of the most comprehensive biometric libraries available. Beyond simple authentication prompts, it offers hardware-backed cryptographic key management, biometric enrollment detection, device integrity checks, StrongBox support, and compatibility with both the React Native New Architecture and Expo. In this article, we'll explore everything this library offers and learn how to integrate biometric authentication into a React Native application.

Why Biometric Authentication?

Traditional authentication methods come with several drawbacks:

• Passwords are easy to forget.
• Weak passwords are vulnerable to attacks.
• OTP-based logins can be slow and frustrating.
• Users often abandon apps with poor login experiences.

Biometric authentication addresses these challenges by providing:

• 🔒 Enhanced security
• ⚡ Faster authentication
• 😊 Better user experience
• 📱 Native platform support
• 🔑 Secure fallback using device credentials

Whether you're building a banking app, healthcare platform, enterprise application, or e-commerce app, biometric authentication has become an expected feature.

Installation

Install the package using npm:

npm install @sbaiahmed1/react-native-biometrics

or with Yarn:

yarn add @sbaiahmed1/react-native-biometrics

For iOS:

cd ios
pod install

Platform Configuration

Before using biometric authentication, configure the required permissions for both Android and iOS.

Android

Open your android/app/src/main/AndroidManifest.xml file and add the following permissions:

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

What do these permissions do?

• USE_BIOMETRIC is the modern Android permission introduced in Android 9 (API 28) for accessing biometric authentication methods such as Fingerprint, Face Unlock, and Iris Scanner.
• USE_FINGERPRINT is included for backward compatibility with older Android versions that rely on the legacy fingerprint authentication API.

Adding both permissions ensures your application supports a wider range of Android devices and OS versions.

iOS

To enable Face ID authentication, add the following entry to your ios/YourApp/Info.plist file:

<key>NSFaceIDUsageDescription</key>
<string>This app uses Face ID for secure authentication.</string>

Why is this required? iOS requires every application requesting Face ID access to provide a usage description explaining why biometric authentication is needed. When your app first requests Face ID permission, users will see a system dialog displaying this message. For example: "This app uses Face ID for secure authentication."

You can customize this message to better match your application's purpose, such as:

• "Authenticate securely using Face ID."
• "Use Face ID to protect your account."
• "Verify your identity before accessing sensitive information."

Display a Simple Authentication Prompt

If your application only requires basic authentication, simplePrompt() provides the quickest implementation.

import {
  authenticateWithOptions,
  isSensorAvailable,
  simplePrompt,
} from '@sbaiahmed1/react-native-biometrics';

const authenticate = async () => {
  try {
    const sensorInfo = await isSensorAvailable();
    if (sensorInfo.available) {
      console.log('TouchID is supported');
      const result = await simplePrompt('Confirm fingerprint');
      if (result) {
        console.log('Successful authentication');
      } else {
        console.log('User cancelled or authentication failed');
      }
    }
  } catch (error) {
    console.log(error);
  }
};

This displays the platform's native biometric dialog without additional customization.

Create a Fully Custom Authentication Experience

For production applications, you'll typically want more control over the authentication dialog. The library allows you to customize the authentication prompt while still using the native system UI.

import {
  authenticateWithOptions,
  isSensorAvailable,
  simplePrompt,
} from '@sbaiahmed1/react-native-biometrics';

const enhancedAuth = async () => {
  try {
    const sensorInfo = await isSensorAvailable();
    if (!sensorInfo.available) return;

    const result = await authenticateWithOptions({
      title: '🔐 Secure Login',
      subtitle: 'Verify your identity',
      description: 'Use your biometric to access your account securely',
      cancelLabel: 'Cancel',
      fallbackLabel: 'Use Password',
      allowDeviceCredentials: true, // Allow PIN/password fallback
      disableDeviceFallback: false, // Enable fallback options
    });

    if (result.success) {
      console.log('✅ Authentication successful!');
      // User authenticated successfully
    } else {
      console.log('❌ Authentication failed:', result.error);
      console.log('🔢 Error code:', result.errorCode);
      // Handle authentication failure
    }
  } catch (error) {
    console.error('💥 Authentication error:', error);
  }
};

Typical Authentication Flow

A recommended authentication flow looks like this:

App Launches
    │
    ▼
Check Sensor Availability
    │
    ▼
Biometrics Available?
    │
    ┌────┴────┐
    │         │
   No        Yes
    │         │
    ▼         ▼
  Login     Show Authentication Prompt
                │
                ▼
          Authentication Successful?
                │
            ┌────┴────┐
            │         │
           Yes       No
            │         │
            ▼         ▼
         Continue   PIN / Password Fallback

Best Practices

When implementing biometric authentication, consider the following recommendations:

• Always check sensor availability before displaying the authentication prompt.
• Provide a fallback authentication method whenever appropriate.
• Never rely solely on biometrics for authorization decisions.
• Use hardware-backed cryptographic keys for sensitive operations.
• Handle user cancellations gracefully.
• Detect biometric enrollment changes to strengthen account security.
• Test on real devices, as simulators may not accurately emulate biometric hardware.

Real-World Use Cases

This library is suitable for a wide range of applications, including:

• Banking and fintech apps
• Healthcare platforms
• Enterprise applications
• Password managers
• Crypto wallets
• Digital signature workflows
• Secure document management
• Government services
• Payment authorization
• Corporate VPN authentication

Conclusion

Whether you're developing a banking app, an enterprise solution, a healthcare platform, or any application that handles sensitive user data, this library offers the flexibility, security, and modern architecture support needed for production-ready biometric authentication.