Send the secret key for an article: https://kolmogorov.pro/integration_google_recaptcha_v3_in_site_on_vue_js

send_recaptcha_secret_key.php

<?php
$secret = 'ВАШ_СЕКРЕТНЫЙ_КЛЮЧ';

$params = array(
'secret' => $secret,
'response' => $_SESSION['recaptcha_token'],
);

$myCurl = curl_init();
curl_setopt_array($myCurl, array(
   CURLOPT_URL => 'https://www.google.com/recaptcha/api/siteverify',
   CURLOPT_RETURNTRANSFER => true,
   CURLOPT_POST => true,
   CURLOPT_POSTFIELDS => http_build_query($params)
));

$response = curl_exec($myCurl);
curl_close($myCurl);

$response = json_decode($response, true);
?>