website/public/API/queries/mailAddress.php

<?php
use GuzzleHttp\Client;

function mailAddress($hCaptchaResponse) {
    require "./lib/config.php";
    $data = array(
        'secret' => $secretkey,
        'response' => $hCaptchaResponse
    );
    $client = new Client();
    
    $response = $client->post("https://hcaptcha.com/siteverify", [
        "form_params" => $data
    ]);
    
    $responseData = json_decode($response->getBody());
    if($responseData->success) {
        return "$contactmail";
    } else {
        return "Fehler beim Validieren des Captchas.";
    }
}