Adding an HTML page to work with Yandex SmartCaptcha

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Updated at April 28, 2025

You can embed SmartCaptcha in your Android and iOS apps via WebView, a component that allows you to display web pages inside an application.

To do this, you need to host an HTML page with CAPTCHA code on your server and then embed the link to this page in the app.

HTML page with a CAPTCHA code

<!DOCTYPE html>
<html>
  <head>
    <title>SmartCaptcha Mobile</title>
    <meta charset="UTF-8" />
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1, shrink-to-fit=no"
    />
    <script>
      function onSmartCaptchaReady() {
        if (!window.smartCaptcha) {
          throw new Error("SmartCaptcha is not present");
        }

        const params = getParameters();

        const widgetId = window.smartCaptcha.render(
          "captcha-container",
          params
        );

        window.smartCaptcha.subscribe(
          widgetId,
          "challenge-visible",
          handleChallengeVisible
        );

        window.smartCaptcha.subscribe(
          widgetId,
          "challenge-hidden",
          handleChallengeHidden
        );

        window.smartCaptcha.subscribe(widgetId, "success", handleSuccess);

        if (params.invisible) {
          window.smartCaptcha.execute(widgetId);
        }
      }

      function handleSuccess(token) {
        if (window.NativeClient) {
          window.NativeClient.onGetToken(token);
        } else {
          sendIos("captchaDidFinish", token);
        }
      }

      function handleChallengeVisible() {
        if (window.NativeClient) {
          window.NativeClient.onChallengeVisible();
        } else {
          sendIos("challengeDidAppear");
        }
      }

      function handleChallengeHidden() {
        if (window.NativeClient) {
          window.NativeClient.onChallengeHidden();
        } else {
          sendIos("challengeDidDisappear");
        }
      }

      function sendIos(...args) {
        if (args.length == 0) {
          return;
        }

        const message = {
          method: args[0],
          data: args[1] !== undefined ? args[1] : ""
        };

        if (window.webkit) {
          window.webkit.messageHandlers.NativeClient.postMessage(message);
        }
      }

      function getParameters() {
        const result = {};

        if (!window.location.search) {
          return result;
        }

        const queryParams = new URLSearchParams(window.location.search);

        queryParams.forEach((value, key) => {
          result[key] = value;
        });

        result.test = result.test === "true";
        result.invisible = result.invisible === "true";
        result.hideShield = result.hideShield === "true";
        result.webview = true;

        return result;
      }
    </script>

    <script
      src="https://smartcaptcha.yandexcloud.net/captcha.js?render=onload&onload=onSmartCaptchaReady"
      defer
    ></script>
  </head>

  <body>
    <noscript>
      You need to enable JavaScript to run this app.
    </noscript>
    <div id="captcha-container" class="smart-captcha" />
  </body>
</html>

You can also add a link to an HTML page on the Yandex Cloud server to your app.

https://smartcaptcha.yandexcloud.net/webview

After that, you will be able to embed SmartCaptcha in your mobile applications:

Adding an HTML page to work with Yandex SmartCaptcha

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