# CVV field handling

In this document we define CVV the 3- or 4-figure number printed on the back of the credit card. It is called in different names according to card issuing company (CVV2 for Visa, 4DBC for American Express, CVC2 for Mastercard).

In all cases it is a number used to increase the security of payments, as it reduces the chance of the credit card being used by someone who is not in possession of it.