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Attack Prevention

How to Use hCaptcha with Android Apps

June 21, 2019

Good news! It is quite simple to integrate hCaptcha with your native Android app today.

(Note: if you are using Flutter, please see our hCaptcha Flutter guide.)

2021 Update
The article below is now outdated: please use our
native Android SDK.

Simply create an HTML file with a hCaptcha form (see hCaptcha docs) and host that on your web site. Then load the URL in a WebView and create a bridge between Java and Javascript (addJavascriptInterface).

Android Activity:

WebView mWebView = (WebView) findViewById(; mWebView.getSettings().setJavaScriptEnabled(true); mWebView.getSettings().setBuiltInZoomControls(false); mWebView.loadUrl("https://your.server/hcaptcha_form.html"); mWebView.addJavascriptInterface(new BridgeWebViewClass(this), "BridgeWebViewClass");

Note: if you are an hCaptcha Enterprise customer, you can also embed the HTML file directly into your mobile app.


in your Activity instead becomes:


Contact the integration engineering team for further guidance to enable this.

Bridge Class:

public class BridgeWebViewClass { @JavascriptInterface public void hCaptchaCallbackInAndroid(String h_response){ log.d("hCaptcha", "token" + h_response); } }

Now from your HTML file you can run the Bridge Class as a Javascript function:

<div class="h-captcha" data-sitekey="YOUR_CAPTCHA_SITE_KEY" data-callback="captchaResponse"></div> <script type="text/javascript"> function captchaResponse(token){ BridgeWebViewClass.hCaptchaCallbackInAndroid(token); } </script>

Finally, pass the response token returned above to your backend server, and have it call siteverify to check that the token is valid.

Let us if you have any questions!

Credit: this method was inspired by a similar StackOverflow answer.

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