Validation Code

A validation code, in the context of Visa transactions, is a 4-digit unique code provided by Visa to verify the authenticity of a credit or debit card during a transaction. This code is one component of the security measures used to prevent fraud and ensure that the card being used is genuine.

The validation code for Visa cards is also known as the Card Verification Value (CVV2). It is typically found on the back of the card, printed separately from the main card number, near the signature strip. For Visa cards, it is precisely the last three digits of the number in the signature area, even though commonly referred to as a "4-digit code," which often aligns more typically with American Express card formats.

During online or telephone transactions where the card is not physically present, the cardholder is asked to provide this CVV2. This extra step helps to confirm that the cardholder has the physical card in their possession and that the card number hasn't been stolen or used improperly.

It's important to note that the CVV2 should never be stored by merchants after the transaction is authorized, according to Payment Card Industry Data Security Standards (PCI DSS) regulations, to further protect cardholder data against unauthorized access or fraud.