<?php

    if (!isset($_POST['recaptcha'])) die('stop spam');

    $secretKey = '(moj klucz prywatny)';
    $token = $_POST['recaptcha'];
    $ip = $_SERVER['REMOTE_ADDR'];

    $url = 'https://www.google.com/recaptcha/api/siteverify?secret=' . $secretKey . '&response=' . $token . '&remoteip=' . $ip;
    $request = file_get_contents($url);
    $response = json_decode($request);

    print_r($response);