Chargeback reason codes sit at the center of the dispute process. Every chargeback includes one. It explains why the cardholder challenged the transaction and defines how the issuer will evaluate the case. For merchants, understanding reason codes is essential.

Chargebacks depend on evidence. Issuers want to see clear data that shows a transaction was valid. Merchants need to provide that data within strict deadlines. The challenge is that many merchants also operate under the General Data Protection Regulation.