How to add recaptcha version 3 to PHP website?

You are going to need recaptcha keys to get started on this. Get it from Google here.

Step 1: JavaScript

Add this JavaScript code between your head tags using script tag or include a seperate .js file in head tags.

grecaptcha.ready(function () {
  grecaptcha
    .execute("YOUR_RECAPTCHA_SITE_KEY", { action: "contact" })
    .then(function (token) {
      var recaptchaResponse = document.getElementById("recaptchaResponse");
      recaptchaResponse.value = token;
    });
});

Step 2: HTML form

Add this line after your submit button but before the form tag ends.

 <form>
    ...
    ...
   <button type="submit">Submit</button>
   <input type="hidden" name="recaptcha_response" id="recaptchaResponse">
 </form>

Step 3: PHP

Use this code for server side integration.

<?php // Check if form was submitted:
if ($_SERVER['REQUEST_METHOD'] === 'POST' &#038;&#038; isset($_POST['recaptcha_response'])) {

    // Build POST request:
    $recaptcha_url = 'https://www.google.com/recaptcha/api/siteverify';
    $recaptcha_secret = 'YOUR_RECAPTCHA_SECRET_KEY';
    $recaptcha_response = $_POST['recaptcha_response'];

    // Make and decode POST request:
    $recaptcha = file_get_contents($recaptcha_url . '?secret=' . $recaptcha_secret . '&#038;response=' . $recaptcha_response);
    $recaptcha = json_decode($recaptcha);

    // Take action based on the score returned:
    if ($recaptcha->score >= 0.5) {
        // Verified - send email
    } else {
        // Not verified - show form error
    }

} ?>

Credit: stevencotterill. Google has nice guides for client side and server side integration as well.

Share this post