A CVV is not always 3 digits, it can vary between 3 and 4 digits, depending on your card provider.

The three-digit CVV code is usually found with card companies such as VISA, Mastercard, JCB, and Discover, etc.

The four-digit CVV is currently only available with the American Express Amex card. Furthermore, the Card Verification Value number (CVV) of this bank is usually known as the Card Identification Code (CID).