An open-source session replay tool developed by highlight.io utilizes rrweb to analyze user interactions and performance regressions within web applications while maintaining minimal impact on user experience. Performance testing revealed that enabling session replay resulted in slight increases in browser resource consumption and interaction latency, yet these changes were negligible enough not to affect user perception adversely. The study, conducted using a React application and Node.js automation, found that while session replay increases memory usage and CPU activity, it does not significantly impact responsiveness, even in scenarios with intensive DOM interactions. The optimal implementation in modern browsers aids in efficiently managing DOM changes, with future goals including profiling the Mutation Observer API to better understand the sources of overhead. The experiment encourages further community engagement and benchmarking across different hardware configurations.