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I’m not a fan of CAPTCHAs as I think you should use less instrusive methods where possible. However, I had to add Google’s reCAPTCHA. It's easy to do. you will just need to create your keys first.

Add this to your page:

<script src=""></script>

Then add this to your form:

<div class="g-recaptcha" data-sitekey="YOUR_SITE_KEY"></div>

This will submit a POST var called g-recaptcha-response. You need to validate this with Google’s server. You can either use cURL or file_get_contents(). Although cURL is more verbose it is more powerful. With file_get_contents() you need to be able to change allow_url_fopen which is unlikely to be an issue — but with cURL it generally works out-of-the-box and is better for handling errors.

Your validation will look something like this:

$data = [

    'secret' => 'YOUR_SECRET_KEY',
    'response' => @$_POST['g-recaptcha-response']


$curl = curl_init();

curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_URL, '');
curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($data));

$response = curl_exec($curl);
$response = json_decode($response, true);

if ($response['success'] === false) {

    // Failure

} else {

    // Success

Tim Bennett is a web designer and developer. He has a First Class Honours degree in Computing from Leeds Metropolitan University and currently runs his own one-man web design company, Texelate.