Additional notes


Updating DCC authorisations

It is possible to perform updates on DCC payments prior to settlement, by submitting a TRANSACTIONUPDATE request.

It is not possible to change the currency of the payment after it has been authorised by the acquiring bank.

It is imperative that all transactions, which use the currency conversions provided by the conversion rate provider, are settled before the dccexpirytimestamp (returned in the CURRENCYRATE response). Failing to do so (e.g. by updating the settlement date) may result in the customer paying the wrong amount and may invalidate your agreement with the conversion rate provider or acquirer.


Partial settlement

You can use a TRANSACTIONUPDATE request to update the settle amount of an authorised DCC payment. This can be used to settle a transaction for a lower value than was initially authorised. The remaining funds will be released by the card issuer once the authorisation code has expired (usually approx. 7 days).

The new settle amount is specified in the settlebaseamount field (this represents the amount in the customer’s currency). It must be lower than the total amount authorised in the customer’s currency.

If a partial settlement request has been processed and the customer has made the payment in the customer’s currency, the original conversion rate of the transaction is used to calculate the respective settle amount in the merchant’s currency.

import securetrading
stconfig = securetrading.Config()
stconfig.username = "[email protected]"
stconfig.password = "Password1^"
st = securetrading.Api(stconfig)
update = {
  "requesttypedescriptions": ["TRANSACTIONUPDATE"],
    "sitereference": [{"value":"test_site12345"}],
    "transactionreference": [{"value":"1-2-3"}]
strequest = securetrading.Request()
stresponse = st.process(strequest) #stresponse contains the transaction response
if (!($autoload = realpath(__DIR__ . '/../../../autoload.php')) && !($autoload = realpath(__DIR__ . '/../vendor/autoload.php'))) {
  throw new Exception('Composer autoloader file could not be found.');
$configData = array(
  'username' => '[email protected]',
  'password' => 'Password1^',
$requestData = array(
'requesttypedescriptions' => array('TRANSACTIONUPDATE'),
'filter' => array(
  'sitereference' => array(array('value' => 'test_site12345')),
  'transactionreference' => array(array('value' => '1-2-3'))
'updates' => array('settlebaseamount' => '960')
$api = \Securetrading\api($configData);
$response = $api->process($requestData);
curl --user [email protected]:Password1^ <DOMAIN>/json/ -H "Content-type: application/json" -H "Accept: application/json" -X POST -d '{
"alias": "[email protected]",
"version": "1.00",
"request": [{
  "requesttypedescriptions": ["TRANSACTIONUPDATE"],
    "sitereference": [{"value":"test_site12345"}],
    "transactionreference": [{"value":"1-2-3"}]
{"alias":"[email protected]","version":"1.00","request":[{"requesttypedescriptions":["TRANSACTIONUPDATE"],"filter":{"sitereference":[{"value":"test_site12345"}],"transactionreference":[{"value":"1-2-3"}]},"updates":{"settlebaseamount":"960"}}]}
<?xml version='1.0' encoding='utf-8'?>
<requestblock version="3.67">
  <alias>[email protected]</alias>
  <request type="TRANSACTIONUPDATE">

Replace <DOMAIN> with a supported domain. Click here for a full list.


Using your own DCC provider

If preferred, you can perform your own currency conversion without performing a CURRENCYRATE request or refer to a pre-existing parent CURRENCYRATE request. To do this, submit an AUTH request (as outlined on this page), while ensuring all the required fields are submitted using valid conversion rate details from your DCC provider.

It is your responsibility to calculate the amounts based on the conversion rates from your DCC provider, and to ensure the amounts and currencies you submit in the AUTH request are valid.
Receipt text

Select acquirers may require certain information to be displayed to the customer in a receipt, following a transaction, such as the conversion rate used and the name of the conversion rate provider. Please be sure to check with your acquiring bank that you are displaying all the information required.


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