Card testing fraud poses a significant threat to online businesses, especially those offering small transaction sizes, as cybercriminals use stolen credit card data to make minor purchases and test the card's validity. This practice can lead to substantial financial losses through chargebacks, additional fees, and potential blacklisting by payment providers, ultimately disrupting legitimate transactions. To mitigate these risks, businesses can implement various anti-fraud measures such as IP address blocking, browser fingerprinting, and using external services like Fingerprint for enhanced fraud detection. While it is challenging to eliminate card testing entirely due to the evolving nature of cyber threats, companies can manage and minimize risks by adopting advanced security tools, setting transaction limits, and requiring additional verification for online purchases. These efforts not only help protect businesses from financial harm but also reassure customers about the security of their transactions, helping maintain trust and a positive customer experience.