September 2025

In September 2025 we updated incremental auth behavior, added a card-network mandates guide, updated Auth API field properties, and added some STIP codes. Click September 2025 to see the details.

Updated incremental auth behavior

We updated our documentation to show that when a network sends an incremental auth request, it sends only the increment, but Galileo immediately combines the increment with the prior amount and presents the cumulative amount as the transaction amount in external data—Auth API, Events API, RDFs, and Program API responses. In Scenario 3, for example, the transaction amounts in the tables remain the same, but the narration in the sequence of events now indicates that the network sends the incremental amount only. This is a change to documentation, not to system behavior.

Card network mandates guide

We added Card Network Mandates, which lists and summarizes mandates from card networks that impact Galileo. (This guide explains the 2025 card network mandates announced to date that impact Galileo and Galileo clients.)

Auth API field properties

We reviewed the field properties (data type, nullability, required) in our Auth API documentation and made some updates. The most important is that all of the amount-type fields—formerly described as floats—are actually strings. This is a change to the documentation, not to system behavior.

You should know that Galileo initializes the Auth API webhook payload by setting all fields to null. As values arrive with the ISO 8583 authorization request, Galileo populates the respective payload fields, including with " " (empty string), according to what the network sends. Our documentation shows the field properties that are most likely. However, variations by network and transaction type mean that a few of the values passed in the webhook payload will vary from what is shown in the documentation.

New STIP codes

We added some new STIP Advice Reason Detail codes for Mastercard.