Using WebView to open the Authgear UI

Learn how to switch between ASWebAuthenticationSession/Custom Tabs to WebKitWebView using Authgear Mobile SDKs.

The default behavior of the Authgear Mobile SDKs is to launch AuthUI in ASWebAuthenticationSession in iOS and Custom Tabs in Android. The latest versions of the mobile SDKs include WebKitWebViewUIImplementation a UIImplementation which makes it possible to customize the above behavior. For example, setting the uiImplementation attribute in the configure() method of the Authgear Capacitor SDK to WebKitWebViewUIImplementation() will open AuthUI using WKWebView on iOS and android.webkit.WebView on Android.

Omitting the uiImplementation attribute in the configure() method will fall back to the default behavior (launching AuthUI in ASWebAuthenticationSession/Custom Tabs). You can also explicitly choose the default behavior by setting uiImplementation to DeviceBrowserUIImplementation().

Example: Setting UIImplementation

The following examples show how to set the uiImplementation attribute.

    clientID: "<CLIENT_ID>",
    endpoint: "<AUTHGEAR_ENDPOINT>",
    isSSOEnabled: true,
    uiImplementation: new WebKitWebViewUIImplementation(),
    tokenStorage: new TransientTokenStorage()

Setting uiImplementation to WebKitWebViewUIImplementation in the above example will change the behavior of your application from using ASWebAuthenticationSession on iOS and Custom Tabs on Android to using WKWebView and android.webkit.WebView respectively.

To set uiImplementation to WKWebView in the native iOS SDK, use WKWebViewUIImplementation or implement your own custom UIImplementation.

Customizing the WebKitWebView UI

WebKitWebViewUIImplementation allows you to customize some parts of the UI. You can do this by passing your customization options as parameters in WebKitWebViewUIImplementation(). You can customize the following parts of the UI:



  • navigationBarBackgroundColor: This option can be used to customize the color of the navigation bar on iOS. The value should be of type UIColor or an integer (React Native or Ionic SDKs) using the following encoding:

  • navigationBarButtonTintColor: This option sets the color of icons and texts on the navigation bar. The value should also be UIColor or an integer (React Native or Ionic SDKs) using the same encoding as navigationBarBackgroundColor.

  • modalPresentationStyle: Sets the type of modal to be shown. The value can be any of the following: "automatic", "fullScreen", "pageSheet".

The following examples show how to set custom background color, tint color, and modal presentation style.

  clientID: "<CLIENT_ID>",
  endpoint: "<AUTHGEAR_ENDPOINT>",
  uiImplementation: new WebKitWebViewUIImplementation({
    ios: {
      modalPresentationStyle: "fullScreen"
    android: {
      actionBarBackgroundColor: 0xffffff00,
      actionBarButtonTintColor: 0xff000000
  tokenStorage: new TransientTokenStorage()

Implementing your Custom UIImplementation

You can implement your own custom UIImplementation when the WebKitWebViewUIImplementation does not meet the requirements of your use case.

The WebKitWebViewUIImplementation class itself is basically a class that implements UIImplementation and overrides the openAuthorizationURL()method. Hence your custom implementation may look like this:

class MyUIImplementation implements UIImplementation {
 async openAuthorizationURL(options: OpenAuthorizationURLOptions):
Promise<string> {
 // Call your own plugin code to implement this.

Then, you can use your custom implementation like this:

 clientID: "my_client_id",
 endpoint: "my_endpoint",
 isSSOEnabled: true,
 uiImplementation: new MyUIImplementation(),

To get a deeper understanding of how to implement your UIImplementation, see the code for the WebKitWebViewUIImplementation implementation.

Unsupported Features and Services

When you drop the default DeviceBrowserUIImplementation to use your own custom UI implementation that uses WebView, it is important to note that you'll be losing the following features and services:

  1. Login with Google: Google prohibits the use of WebKitWebView with the Google SSO. Learn more here: As a result WebKitWebViewUIImplementation and Google SSO cannot be used together.

  2. Passkey: Passkey is not supported in WebKitWebView.

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