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Redirect to PayGate

This section explains how to handle the Redirect message returned by PayGate when a customer must be redirected to complete a payment.

What is Returned in the Redirect Message?

The Redirect message includes:

  • A dynamic URL

  • A set of KeyValuePairs that must be POSTed to that URL

Typical data includes:

  • PAYGATE_ID

  • PAY_REQUEST_ID

  • TRANSACTION_ID

  • CHECKSUM

⚠️

Important: The redirect data is dynamic. Always iterate through each KeyValuePair instead of hardcoding field names.

Redirect Methods

There are two implementation options:

1. Standard Redirect (Form POST)

Post the redirect fields to the PayGate endpoint using a form submission:

<form action="https://secure.paygate.co.za/payhost/redirect.trans" name="frmSubmit" id="frmSubmit" method="post">
  <input type="hidden" name="PAYGATE_ID" value="10011072130" />
  <input type="hidden" name="PAY_REQUEST_ID" value="7B44FC55-CA90-1922-B32D-00DD010772DB" />
  <input type="hidden" name="CHECKSUM" value="5670e03e6c66ac4f7dac32f553a7f9c2" />
</form>
<script>document.forms["frmSubmit"].submit();</script>

2. Redirect Inside an IFRAME

Same as above, but the form's target must match the IFRAME’s id.

<form action="https://secure.paygate.co.za/payhost/redirect.trans" method="post" target="iframeID">
  <!-- Hidden inputs as above -->
</form>
<iframe id="iframeID"></iframe>
📘

GET requests will not work — you must use POST for all redirections.

Example Values Returned

FieldDescription
URLRedirect endpoint
PAYGATE_IDMerchant ID
PAY_REQUEST_IDTransaction ID
CHECKSUMMD5 hash for verification

Checksum Calculation (Outbound)

Use this format to generate a checksum:

$encryptionKey = 'test';

$data = array(
  'PAYGATE_ID'     => 10011072130,
  'PAY_REQUEST_ID' => '7B44FC55-CA90-1922-B32D-00DD010772DB',
  'REFERENCE'      => 'Customer1'
);

$checksum = md5(implode('', $data) . $encryptionKey);
// Output: 5670e03e6c66ac4f7dac32f553a7f9c2
📘

Always recalculate and validate the checksum before sending or accepting a redirect.

Redirect Back to Merchant

After authentication or payment, the customer is redirected back to your site via the ReturnUrl you supplied.

Redirect Payload

Standard HTTP POST with hidden form fields:

PAY_REQUEST_ID=7B44FC55-...&TRANSACTION_STATUS=1&CHECKSUM=d88fa44173...
FieldDescription
PAY_REQUEST_IDUnique reference used earlier
TRANSACTION_STATUSFinal transaction result (e.g. 1 = Approved)
CHECKSUMMD5 hash (see below)

Checksum Calculation (Inbound)

$encryptionKey = 'test';

$data = array(
  'PAYGATE_ID'         => 10011072130,
  'PAY_REQUEST_ID'     => '7B44FC55-...',
  'TRANSACTION_STATUS' => 1,
  'REFERENCE'          => 'Customer1'
);

$checksum = md5(implode('', $data) . $encryptionKey);
// Output: 802d69d20233e59406cca749e79d7421

Concatenate:

PAYGATE_ID + PAY_REQUEST_ID + TRANSACTION_STATUS + REFERENCE + KEY

Example:

100110721307B44FC55-...1Customer1test