Payment integrity monitoring is a defensive detection practice that watches payment systems for signs that a transaction, approval step, or authorization rule has been manipulated. It looks for abnormal transaction timing, unusual amounts or destinations, new payee or merchant activity, unexpected client enrollments, changes in approval patterns, and suspicious API or workflow behavior.
It matters because many payment attacks do not begin with obvious malware. Attackers often abuse valid credentials, certificates, or trusted systems to make fraudulent transfers look legitimate. Monitoring integrity helps defenders catch that misuse by correlating transaction logs, identity events, and workflow changes before money moves or settlement becomes difficult to reverse. In practice, it complements endpoint and network security by focusing on business logic and payment behavior, not just files or alerts.