EMV (Chip Card) Tag Classification

About a year and a half ago, one of my long-established clients engaged me to devise a way to extend their custom retail payment processing application to support EMV card processing. As I dug into the EMV specification, I realized that the many tags (so called because they arrive as XML document tags) fell into natural groups that corresponded to various use cases based on transaction type and approval status.

I identified four transaction types.

1. Payment is a request for authorization to charge a card to pay for a purchase.
2. Credit Memo is a request to credit a customer's account, for example, when an item is rung up incorrectly, or to settle a grievance with an unhappy customer.
3. Void is a request to unwind (discard) a transaction (usually a Payment).
4. Authorization is a request to verify that there are sufficient funds available to cover a future Payment, such as the overnight rental of a hotel room or the reservation for a future rental.

There are three possible outcomes for any of the above transactions.

1. Approved is a transaction that is either fully or partially approved.
2. Declined is a transaction for which approval is declined outright, for any number of reasons, such as over limit, expired card, account closed, card reported stolen, or other reasons.
3. No Response is a transaction that elicits no response from the gateway, for example, when the merchant's Internet connection is down.

The tags (fields) that must be printed on the customer's receipt vary, depending primarily on the response (approved, declined, or no response), and, to a lesser extent, on the transaction type.

EMV Receipt Fields is the two Excel worksheets, formatted for printing, that I created to serve as the basis for the data model that I created for the client. Since the EMV card specification is an international standard, anyone who is tasked with supporting it should be able to use the tables.