What is a CVV Credit Card Code?

A "Card Verification Value" (or "CVV") is a 3-digit security authentication number printed on the back of credit cards. It is typically used for online purchases. For Visa (CVV), MasterCard, (CVC) and Discover cards (CID), the card code is the last 3 digit number located on the back of the card on or above the signature line. For an American Express card, it is the 4 digits on the front above the end of the card number.