AVS stands for Address Verification Service. AVS is required for all card-not-present (keyed) credit card transactions. At the time of the transaction, simply enter the street address and postcode along with the card number, expiration date and amount. When the transaction is submitted for authorisation, the address and postcode are checked against the billing address and postcode for the cardholder. The AVS response is provided by the issuing bank and the result is either a match, partial match, no match, or AVS not available/error.