Ingress Replay Protection is a security feature developed by Fingerprint to combat advanced fraud tactics where attackers impersonate legitimate users by replaying captured data payloads. This tactic involves intercepting and re-sending genuine user requests, which can bypass traditional fraud checks due to their authenticity. Fingerprint addresses this threat by remembering the unique signatures of incoming requests for a short period, flagging any reuse as a potential replay attack with a "replayed: true" marker. This feature provides real-time visibility and alerts without adding latency or altering the request, allowing security-conscious industries like banking and fintech to enhance their fraud detection and risk scoring processes. By silently detecting and flagging suspicious reuses, it enables teams to preemptively address threats without alerting attackers, thus improving security measures for high-value transactions.