This plugin for Capacitor 4 provides access to native biometry on iOS and Android. It supports every type of biometry and every configuration option on both platforms. In addition, biometry is simulated on the web so you can test your logic without making any changes to your code.
👉 NOTE: This plugin only works with Capacitor 4. If you are upgrading from the Capacitor 2 version, note that the plugin name has changed to BiometricAuth.
🛑 BREAKING CHANGE: If you are upgrading from a version prior to 3.0.0, please note that androidMaxAttempts is no longer supported. See the documentation for authenticate() for more information.
Here is capacitor-biometric-auth running on the demo app on both iOS and Android.
| iOS | Android |
|---|---|
ios.mp4 |
android.mp4 |
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The API is extensively documented in the TypeScript definitions file. There is also (somewhat incomplete auto-generated) documentation below. For a complete example of how to use this plugin in practice, see the demo app.
Before giving the user the option to use biometry (such as displaying a biometry icon), call checkBiometry and inspect the CheckBiometryResult to see what (if any) biometry is available on the device. Note that isAvailable may be false but biometryType may indicate the presence of biometry on the device. This occurs if the current user is not enrolled in biometry, or if biometry has been disabled for the current app. In such cases the reason will tell you why.
Because the availability of biometry can change while your app is in the background, it’s important to check availability when your app resumes. By calling addResumeListener you can register a callback that is passed a CheckBiometryResult when your app resumes.
Once you have determined that biometry is available, to initiate biometric authentication call authenticate. authenticate takes an AuthenticateOptions object which you will want to use in order to control the behavior and appearance of the biometric prompt.
If authentication succeeds, the Promise resolves. If authentication fails, the Promise is rejected with a BiometryError, which has two properties:
| Property | Type | Description |
|---|---|---|
| message | string | A description of the error suitable for debugging |
| code | BiometryErrorType | What caused the error |
On the web, you can fake any of the supported biometry types by calling setBiometryType().
On iOS, Touch ID and Face ID are supported.
On Android, fingerprint, face, and iris authentication are supported. Note that if a device supports more than one type of biometry, the plugin will only present the primary type, which is determined by the system.
checkBiometry()setBiometryType(...)authenticate(...)addResumeListener(...)- Interfaces
- Type Aliases
- Enums
checkBiometry() => Promise<CheckBiometryResult>Check to see what biometry type (if any) is available.
Returns: Promise<CheckBiometryResult>
setBiometryType(type: BiometryType | string | undefined) => Promise<void>web only
On the web, this method allows you to dynamically simulate different types of biometry. You may either pass a BiometryType enum or the string name of a BiometryType. If a string is passed and it isn't a valid value, nothing happens.
| Param | Type |
|---|---|
| type | string | BiometryType |
authenticate(options?: AuthenticateOptions) => Promise<void>Prompt the user for authentication. If authorization fails for any reason, the promise is rejected with a BiometryError.
For detailed information about the behavior on iOS, see:
https://developer.apple.com/documentation/localauthentication/lapolicy/deviceownerauthenticationwithbiometrics
Android imposes a limit of 5 failed attempts. If allowDeviceCredential is true, the user will then be presented with a device credential prompt. If allowDeviceCredential is false, authenticate() will reject with a BiometryErrorType of biometryLockout, after which the user will have to wait 30 seconds before being allowed to authenticate again.
| Param | Type |
|---|---|
| options | AuthenticateOptions |
addResumeListener(listener: ResumeListener) => Promise<PluginListenerHandle>Register a function that will be called when the app resumes. The function will be passed the result of checkBiometry().
| Param | Type |
|---|---|
| listener | ResumeListener |
Returns: Promise<PluginListenerHandle>
| Prop | Type | Description |
|---|---|---|
| isAvailable | boolean | True if the device has biometric authentication capability and the current user has enrolled in biometry. |
| biometryType | BiometryType | The type of biometry available on the device. |
| reason | string | If biometry is not available and the system gives a reason why, it will be returned here. Otherwise it's an empty string. |
| Prop | Type | Description |
|---|---|---|
| reason | string | The reason for requesting authentication. Displays in the authentication dialog presented to the user. If not supplied, a default message is displayed. |
| cancelTitle | string | iOS: The system presents a cancel button during biometric authentication to let the user abort the authentication attempt. The button appears every time the system asks the user to present a finger registered with Touch ID. For Face ID, the button only appears if authentication fails and the user is prompted to try again. Either way, the user can stop trying to authenticate by tapping the button. Android: The text for the negative button. This would typically be used as a "Cancel" button, but may be also used to show an alternative method for authentication, such as a screen that asks for a backup password. Default: "Cancel" |
| allowDeviceCredential | boolean | If true, allows for authentication using device unlock credentials. Default is false. iOS: If biometry is available, enrolled, and not disabled, the system uses that first. After the first Touch ID failure or second Face ID failure, if iosFallbackTitle is not an empty string, a fallback button appears in the authentication dialog. If the user taps the fallback button, the system prompts the user for the device passcode or the user’s password. If iosFallbackTitle is an empty string, no fallback button will appear.If biometry is not available, enrolled and enabled, and a passcode is set, the system immediately prompts the user for the device passcode or user’s password. Authentication fails with the error code passcodeNotSet if the device passcode isn’t enabled.If a passcode is not set on the device, a passcodeNotSet error is returned.The system disables passcode authentication after 6 unsuccessful attempts, with progressively increasing delays between attempts. The title of the fallback button may be customized by setting iosFallbackTitle to a non-empty string.Android: The user will first be prompted to authenticate with biometrics, but also given the option to authenticate with their device PIN, pattern, or password by tapping a button in the authentication dialog. The title of the button is supplied by the system. |
| iosFallbackTitle | string | The system presents a fallback button when biometric authentication fails — for example, because the system doesn’t recognize the presented finger, or after several failed attempts to recognize the user’s face. If allowDeviceCredential is false, tapping this button dismisses the authentication dialog and returns the error code userFallback. If undefined, the localized systetm default title is used. Passing an empty string hides the fallback button completely.If allowDeviceCredential is true and this is undefined, the localized system default title is used. |
| androidTitle | string | Title for the Android dialog. If not supplied, the system default is used. |
| androidSubtitle | string | Subtitle for the Android dialog. If not supplied, the system default is used. |
| Method | Signature |
|---|---|
| remove | () => Promise<void> |
The signature of the callback passed to addResumeListener().
(info: CheckBiometryResult): void
| Members | Description |
|---|---|
| none | No biometry is available |
| touchId | iOS Touch ID is available |
| faceId | iOS Face ID is available |
| fingerprintAuthentication | Android fingerprint authentication is available |
| faceAuthentication | Android face authentication is available |
| irisAuthentication | Android iris authentication is available |