CVV

The CVV number is the three- or four-digit number on the back or in front of your card that provides added security when making purchases online, over the phone, or in person. For Visa, Mastercard, and Discover cards, the CVV number is three digits long and appears on the back of your card to the right of your signature. American Express cards have a four-digit code located on the front. This code helps verify that you are in possession of your physical credit or debit card - not just any old card number that may have been stolen - when making an online transaction.