AVS is short for Address Verification System, which simply tries to map/match the the address given with the card holder’s address. This technology by it’s implementation is a weak one, and cannot be highly regarded due to several reasons: A recent change in address causes negative responses. Service only available in US and a few EU countries.
AVS provides following common results:
A – The address matched, but the zip code did not. This is for Mastercard, Visa, and AMEX users.
Y – Address matched, but the zip code did not for a Discover card user.
B – The street address was a match, but the postal code was in the wrong format for the international user.
C – The street addresses and postal codes were formatted incorrectly.
D – The street address and postal code match for an international user.
E – There was an error.
G – The service is not supported by a non-US user.
I – Address information was not verified by the international issuer.
M – T street address and postal code match for an international user.
N – There is no match for the zip code or the address.
O – No Response was sent.
P – While the postal codes match, the street addresses cannot be verified due to inconsistencies in the formats.
R – You should retry. The system is temporarily unavailable or has timed out.
S – The server is not supported by the user.
U – The address information is unavailable.
W – The nine digit zip code matches, but the address does not.
X – This is an exact match.
Y – Both the address and the zip code match.
Z – The five-digit zip code matches, but the address does not.
0 – There is no response.
Unless your customer base is not US only, do not use AVS. Just IP to county/city mapping will bring more information.