require_once 'vendor/autoload.php'; 
use GuzzleHttp\Client; 

$client = new GuzzleHttp\Client();
<!-- $res = $client->request('GET', 'https://api.github.com/user', [
    'auth' => ['user', 'pass']
]); -->
$res = $client->request('GET', 'https://freetestapi.com/api/v1/cats');
echo $res->getStatusCode();
// "200"
echo $res->getHeader('content-type')[0];
// 'application/json; charset=utf8'
echo $res->getBody();