Account takeovers (ATOs) pose a significant threat to online platforms, with attackers often exploiting leaked credentials through techniques like credential stuffing. Datadog has developed an automated system to combat ATOs by conducting real-time checks during login events to identify compromised credentials, using a k-anonymity technique to ensure user privacy. This approach allows Datadog to reset passwords proactively when a breach is detected, reducing the need for manual intervention and minimizing disruption to the user experience. The system, which focuses on password-based authentication, operates in the background to provide enhanced security without impacting login times. Future plans include expanding protections beyond passwords to address threats like cookie theft and deepening integration with the Safety Center for better visibility into credential exposures.