recaptcha-backend-v3.php

<?php
        function httpPost($url, $data){
            $curl = curl_init($url);
            curl_setopt($curl, CURLOPT_POST, true);
            curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($data));
            curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
            $response = curl_exec($curl);
            curl_close($curl);
            return $response;
        }
        if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['g-recaptcha-response'])) {
        
            // Build POST request:
            $recaptcha_url = 'https://www.google.com/recaptcha/api/siteverify';
            $recaptcha_secret = 'YOUR_SECRET';
            $recaptcha_response = $_POST['g-recaptcha-response'];
        
            // Make and decode POST request:
            $data = array(
                'secret' => $recaptcha_secret,
                'response' => $recaptcha_response
            );
            $recaptcha = httpPost($recaptcha_url,$data);
            $recaptcha = json_decode($recaptcha);
            // Take action based on the score returned:
            if ($recaptcha->score < 0.5) {
                header("Location:fail.html?bot=1");
                die();
            }
        
        }else{
            echo "bot checking error, token missing";
            die();
        }
?>