There are two fields to pass your order ID and the purpose to the transaction. The order ID helps you to connect with your system. The purpose is shown at the bank statements of the customer, but also in your advice notes for the payout.
The field names are:
merchantRef
: your order ID;transactionRef
: purpose text.
Example request body:
Smart Transaction
{
...
"merchantRef"
:
"500015241"
,
"transactionRef"
:
"Müller Sep/25/2020-Sep/29/2020"
,
...
}
Neither order ID nor purpose are visible in Smart Checkout.