Face ID Before the Paywall: A Bubble.io iOS WebView Pattern with WebViewGold’s Bio Auth API

Implementing Face ID before a paywall inside an iOS WebView app built with Bubble.io requires a reliable bridge between the web layer and native biometric hardware. WebViewGold’s Bio Auth API provides exactly that bridge, letting you trigger native Face ID authentication directly from JavaScript inside the WebView. This pattern keeps premium content locked behind biometric verification without exposing any native code to your Bubble app.

Understanding the Challenge

Bubble.io applications run as web content inside a WebView shell when packaged as native apps. Standard web technologies cannot access Face ID or Touch ID on iOS devices. A paywall that relies only on username and password creates friction, and a paywall that skips authentication entirely weakens security. The goal is to show the paywall only after the user successfully authenticates with Face ID, all while keeping the user experience smooth and native.

The WebViewGold Bio Auth API

WebViewGold exposes a JavaScript interface that lets your Bubble app call native biometric authentication methods. The API is available on the global window object when the app runs inside a WebViewGold wrapper. You call a single method, pass a reason string, and provide a callback function for success or failure. This design keeps all business logic in your Bubble workflows while the native layer handles the secure enclave operations.

Bubble.io Integration Approach

Inside your Bubble editor, you add a custom JavaScript snippet that runs before revealing the paywall group. This snippet checks for the WebViewGold bridge, triggers Face ID authentication, and then calls back into a Bubble workflow using a custom event or a JavaScript-to-Bubble plugin. The paywall group remains hidden by default and becomes visible only after a successful authentication callback.

Step by Step Implementation

First, create a hidden group in your Bubble page that contains the paywall content. Give this group a unique ID so you can control its visibility from JavaScript. Second, add an HTML element to the page and paste the following script that defines the authentication function. Third, create a custom event in Bubble named showPaywall and another named showAuthError. Fourth, wire these custom events to show or hide the appropriate groups. Fifth, call the authentication function from a button click or page load workflow.

function authenticateBeforePaywall() {
    if (window.webviewgold && window.webviewgold.bioAuth) {
        window.webviewgold.bioAuth.authenticate(
            "Authenticate to access premium features",
            function(success) {
                if (success) {
                    window.bubbleFn.showPaywall();
                } else {
                    window.bubbleFn.showAuthError();
                }
            }
        );
    } else {
        window.bubbleFn.showPaywall();
    }
}

The fallback branch handles cases where the app runs in a plain browser or a non-WebViewGold wrapper. In those environments, you may choose to show the paywall directly or use an alternative authentication method. The key is to avoid blocking legitimate users while maintaining security inside the native app.

Handling the Paywall Display

The Bubble custom events receive the success or failure signal from JavaScript. The showPaywall event sets the paywall group to visible and scrolls to it. The showAuthError event displays a brief message and offers a retry button that calls the same authentication function again. This keeps the feedback loop tight and prevents users from bypassing Face ID by simply dismissing the prompt.

Testing on Device

Face ID does not function in the iOS Simulator the same way it does on a physical device. You must test the full authentication flow on a real iPhone or iPad with Face ID enrolled. WebViewGold’s Bio Auth API also respects the system setting for biometric enrollment, so if the user has disabled Face ID, the API returns a failure or prompts for the device passcode depending on your wrapper configuration. Always test both the success and failure paths.

A Note on Android

WebViewGold also offers a quick and simple solution to convert websites into apps for Android easily. The same Bio Auth API pattern works on Android using fingerprint or face unlock, letting you reuse your Bubble logic across both platforms with minimal changes. This cross-platform consistency reduces development time and keeps your authentication flow uniform.

Conclusion

Adding Face ID before a paywall in a Bubble.io iOS WebView app becomes straightforward when you leverage WebViewGold’s Bio Auth API. The pattern separates native security from web logic, keeps your Bubble workflows clean, and provides a seamless user experience. Implement the hidden paywall group, the JavaScript bridge, and the custom events, then test on device to confirm everything works as expected.

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More Information & Download App Template: WebViewGold