require 'vendor/autoload.php';

    //if you want to change the namespace/path from 'KroozPay' - lines[1-5] - to your desired name,
    i.e. (use KroozPay\Api\Amount; to use MyDomain\Api\Amount;), then you must change the folders name that holds
    the API classes as well as change the property 'KroozPay' in (autoload->psr-0) of (php-sdk/composer.json) file to your
    desired name and run "composer dump-autoload" command from sdk root

    use KroozPay\Api\Payer;
    use KroozPay\Api\Amount;
    use KroozPay\Api\Transaction;
    use KroozPay\Api\RedirectUrls;
    use KroozPay\Api\Payment;

    //Payer Object
    $payer = new Payer();
    $payer->setPaymentMethod('KroozPay'); //preferably, your system name, example - KROOZ PAY

    //Amount Object
    $amountIns = new Amount();
    $amountIns->setTotal(20)->setCurrency('USD'); //must give a valid currency code, code must exist in merchant wallet

    //Transaction Object
    $trans = new Transaction();
    $trans->setAmount($amountIns);

    //RedirectUrls Object
    $urls = new RedirectUrls();
    $urls->setSuccessUrl('http://your-merchant-domain.com/example-success.php') //success url - the merchant domain page,
    to redirect after successful payment, see sample example-success.php file in sdk root,
    example - https://kroozpay.com/gateway/example-success.php
    ->setCancelUrl('http://your-merchant-domain.com/'); //cancel url - the merchant domain page, to redirect after
    cancellation of payment, example -  https://kroozpay.com/gateway

    //Payment Object
    $payment = new Payment();
    $payment->setCredentials([ //client id & client secret, see merchants->setting(gear icon)
    'client_id' => 'place your client id here', //must provide correct client id of an express merchant
    'client_secret' => 'place your client secret here' //must provide correct client secret of an express merchant
    ])->setRedirectUrls($urls)
    ->setPayer($payer)
    ->setTransaction($trans);

    try {
     $payment->create(); //create payment
     header("Location: ".$payment->getApprovedUrl()); //checkout url
    } catch (Exception $ex) {
     print $ex;
     exit;
    }