website/public/API/getMail.php

<?php
include("./lib/config.php");

require("./vendor/autoload.php");
use GuzzleHttp\Client;

$data = array(
    'secret' => $secretkey,
    'response' => $_POST['h-captcha-response']
);
$client = new Client();

$response = $client->post("https://hcaptcha.com/siteverify", [
    "form_params" => $data
]);

$responseData = json_decode($response->getBody());
if($responseData->success) {
    echo("$contactmail");
} else {
    echo("Failed to verify Captcha");
}