Biometric Authentication in React Native

Biometric Authentication in React Native

Biometric authentication, such as fingerprint scanning and face recognition, is a standard feature in modern mobile applications. It provides a convenient and secure way for users to authenticate without typing a password. React Native and Expo make it easy to add biometric authentication to your app.

Expo provides the expo-local-authentication library, which lets you check if the device supports biometric authentication and prompt the user to authenticate. The library works with Face ID and Touch ID on iOS, and with fingerprint scanners and face recognition on Android. It handles the complexity of different hardware and software implementations across devices.

The basic flow is: first, check if biometric authentication is available on the device using hasHardwareAsync and isEnrolledAsync. Then, call authenticateAsync to prompt the user. The function returns a result indicating whether the authentication was successful. You can customize the prompt message and handle cases where the user cancels or the authentication fails.

Biometric authentication is often used as a secondary authentication method, after the user has logged in with a password. Once the user's identity is verified, you can store a token securely on the device using expo-secure-store. On subsequent launches, you can prompt for biometric authentication and use the stored token to access the app. This provides a seamless and secure user experience.