Scenario – Installment Payments
You offer your customers payment by credit card based on installment payments
Customers agrees installment payment based on a total amount and a number of installment payments.
You use the pseudo card number to store and reuse the card data
IMPORTANT: The following initial payment is subject to the liability shift for you as a merchant. In the case of the subsequent payment, however, this expires, so that there is no liability shift.
 credentialOnFile has been extended with type=installments and a few attributes describing the installment payment.
Credentials on File (CoF) – Initial Installment Payment
Applies to PaySSL.aspx + PayNow.aspx
3-D Secure is mandatory
Necessary adjustments:
Example:
JSON object credentialOnFile with JSON parameter installment (3 keys included)
JSON object credentialOnFile with JSON parameter initialPayment and the value "true"
- the amount used for the initial payment request is the amount authorized for 1st installment payment
Example Initial Subscription Payment for 3 installment payments with a total amount of 100,00 (EUR):
{
"type": {
"installments": {
"total": 3,
"curIdx": 1,
"purchaseAmount": 10000
}
},
"initialPayment": true
}
Credentials on File (CoF) – Subsequent Installment Payment
Applies to installment.aspx
3-D Secure is NOT mandatory
Necessary adjustments:
Example:
- The PayId from the initial payment is required for each subsequent installment payment.
- Please always send the schemereferenceID from the initial payment so that the downstream systems can link the two transactions accordingly.
JSON object credentialOnFile with JSON parameter recurring (3 keys included)
JSON object credentialOnFile with JSON parameter initialPayment and value "false"
- the total purchase amount (purchaseAmount) and total number of installment payments (total) remain the same, the current index increases with each authorization.
- the amount used for the subsequent payment request is the amount authorized for subsequent installment payment
Example Subsequent Subscription Payment:
{
"type": {
"installments": {
"total": 3,
"curIdx": 2,
"purchaseAmount": 10000
}
},
"initialPayment": false
}
Request / Response installment.aspx
Request Elements
Notice: For security reasons, Computop Paygate rejects all payment requests with formatting errors. Therefore, please use the correct data type for each parameter. The following table describes the encrypted payment request parameters:
PayID in request always refers to initial Payment created with PaySSL or PayNow
PayID in response is the new payment process created for the subsequent installment payment
Response Elements (installments)
The following table describes the result parameters with which the Computop Paygate responds to your system pls. be prepared to receive additional parameters at any time and do not check the order of parameters the key (e.g. MerchantId, RefNr) should not be checked case-sentive