Mainframes remain integral to global financial transactions, yet modern technologies such as Kafka, ksqlDB, and Apache Cassandra are revitalizing mainframe operations at Broadcom. The Mainframe Operational Intelligence (MOI) product utilizes these technologies to collect and analyze performance metrics from mainframes, addressing challenges like high metric variability and false-positive alerts. A prototype using ksqlDB demonstrates its potential as a filtering tool for anomaly detection by employing SQL-like rules to manage streams of metrics. This involves creating streams with specific rules to filter and flag alerts based on metric values. Despite challenges such as schema compatibility, the integration of ksqlDB into MOI has shown promising results in enhancing the system's efficiency. The effort reflects a broader trend of integrating innovative data processing tools to improve legacy systems, supported by a responsive community and comprehensive resources, as evidenced by Skai's success in overhauling its ad-campaign dashboard using similar technologies.