Reducing spam by adding Google reCAPTCHA

reCAPTCHA embeds a CAPTCHA in your page to help prevent spam. reCAPTCHA requires additional configuration in the Site Settings.

Gif of Google ReCAPTCHA succesfully verifying

To add reCAPTCHA to your site:

  1. Sign up for an API key at
  2. Add the form element by following the instructions at the reCAPTCHA documentation.
  3. Add the secret and key to Site Settings / Forms
Screenshot of reCAPTCHA setup interface

Once configured, any form submissions that fails to validate will return a 401 error page.

Screenshot of form-submission failure screen


Additional JavaScript is required to use reCAPTCHA v3 with CloudCannon forms. This is to add the required input named g-recaptcha-response before submitting. An example of how to set this up is:

  1. Add your form to the HTML
  2. Include the reCAPTCHA script tag with your Site ID
  3. Add JavaScript to catch form submissions
  4. Generate the recaptcha token
  5. Add token to a new input named g-recaptcha-response
  6. Resubmit the form

HTML Form:

<form method="post" id="my-form" action="/contact-success">
  <label for="email_address">Email Address</label>
  <input id="email_address" type="text" name="email">

  <label for="message">Message</label>
  <textarea id="message" name="message"></textarea>

  <input type="hidden" name="_to" value="{{ }}">
  <input type="text" name="_gotcha" style="display: none;">

  <input type="submit" value="Send Message">


<script src=""></script>
  var submitted = false;
  var tokenCreated = false;
  var formEl = document.getElementById('my-form');

  formEl.addEventListener("submit", function (event) {

    // Check if the recaptcha exists
    if (!tokenCreated) {

      // Prevent submission

      // Prevent more than one submission
      if (!submitted) {
        submitted = true;
        // needs for recaptacha ready
        grecaptcha.ready(function() {
          // do request for recaptcha token
          // response is promise with passed token
          grecaptcha.execute('SITE_ID', {action: 'create_comment'}).then(function (token) {
            // add token to form
            var input = document.createElement("input");
            input.type = "hidden";
   = "g-recaptcha-response";
            input.value = token;

            // resubmit the form
            tokenCreated = true;
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Other Resources

  1. Recaptcha Home
  2. Recaptcha Documentation