PCI Compliance is the adherence to PCI DSS guidelines, established by major credit card brands (Visa, Mastercard, American Express, Discover, and JCB). The standard consists of 12 requirements, divided into six categories: Build and Maintain a Secure Network, Protect Cardholder Data, Maintain a Vulnerability Management Program, Implement Strong Access Control Measures, Regularly Monitor and Test Networks, and Maintain an Information Security Policy.