The Card Verification Code (CVV or CVV2) is a security feature to help verify that you are in possession of the credit card and not using a stolen credit card number. The CVV is required by most merchants for online “card not present” transactions and helps reduce fraud. The 3-digit CVV code can be found on the back of a Visa, Mastercard, or Discover card in the Signature area after the last 4 digits of the credit card number. On an American Express card, the 4-digit CVV code is located on the front of the card, above the credit card number.