Product overview

Rationale

Where the final amount will exceed or is likely to exceed the amount of the pre-authorization (including any scheme allowed percentage variation), a further incremental authorization may be obtained. The incremental authorization will be for the difference between the original pre-authorization and the actual or estimated final amount. The sum of all linked estimated and incremental authorizations represent the total amount on hold in the cardholder’s account for a given transaction.

By using incremental authorizations merchants can ensure the cardholder’s open-to-buy accurately reflects their transaction activity.

Schemes

Acquirer

Authorization Validity

The 30 day chargeback protection timeframe is calculated from the date of the last approved authorization. Thus, an incremental authorization may be submitted to extend the chargeback protection period for the same transaction. 

Message Flow

A regular incremental authorization sequence consists of three parts:

• The original pre-authorization itself
• An incremental transaction with an amount update to add to the original pre-authorization amount
• At a later time a capture transaction referring to the incremental transaction

Reversals

If an incremental authorization is being reversed, the amount being reversed is just that of the increment. A pre-authorization for the original amount will exist at the host (if it has not expired). Please note that to date it is not possible to reverse a pre-authorization and all its increments in one message. Each increment must be reversed individually starting with the latest incremental transaction before the original pre-authorization can be cancelled.

Card Authentication and Cardholder Verification

All pre-authorizations and incremental authorizations must occur online and if it is an EMV transaction it has to supply full EMV data for the transaction. The incremental transaction might be a ‘card-present’ or a ‘card-not-present’ transaction. Therefore it is possible or even likely that the initial preauthorization is an EMV transaction but not the increment. This is permitted as it can be assumed that card authentication and cardholder verification were perused in the initial pre-authorization.

Message Linking

For a given transaction, the original authorization request, the incremental authorization requests, and the reversal request are linked together by unique values referred to as tracing data. For Paygate merchants this link will be established towards the acquirer automatically through the PayID.

Process flow chart

Paygate interface

Definitions

Data formats

Abbreviations

Notice: Please note that the names of parameters can be returned in upper or lower case.

Call of interface for incremental authorisation

 To carry out an incremental authorisation via a Server-to-Server connection, please use the following URL:

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:

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. mid, RefNr) should not be checked case-sentive

Response parameters for incremental authorisation