UPS

$curl = curl_init();

            $payload = "grant_type=authorization_code&code=".$_GET['code']."&redirect_uri=https://mdeliverywine.co.uk/ups/callback&client_id=4AGdWW41GyA3ehKAM3OzyK5vZiLgnXBxrjSfdkrYqY2PxXbV";

            curl_setopt_array($curl, [
                CURLOPT_HTTPHEADER => [
                    "Content-Type: application/x-www-form-urlencoded",
                    "Authorization: Basic bWRlbGl2ZXJ5NDgyOnp5bmhpay1jb3d3RWQtM3FpeHJ1"
                ],
                CURLOPT_POSTFIELDS => $payload,
                CURLOPT_URL => "https://wwwcie.ups.com/security/v1/oauth/token",
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_CUSTOMREQUEST => "POST",
            ]);

            $response = curl_exec($curl);
            $error = curl_error($curl);

            curl_close($curl);

            if ($error) {
                echo "cURL Error #:" . $error;
            } else {
                echo $response;
            }