OpenResty XRay is a SaaS platform for diagnosing and optimizing various software systems at real time. It can look directly inside running software systems without changing or affecting the state of the target systems at all. All the internal execution details and dynamically changing data structures can all be inspected and analyzed on demand, and the results are shown to the users through visualizations such as flame graphs and many more. The system has the ability to automatically reason about the root causes of system anomalies via our proprietary inference engine and knowledge base.