Node.js is an event-driven platform where the event loop, managed by the libuv library, orchestrates the execution of callbacks in a single thread, contrary to common misconceptions that involve separate threads or an extensive use of thread pools. The event loop consists of distinct phases—such as timers, I/O callbacks, polling, setImmediate, and close—that manage different tasks. Monitoring the event loop involves metrics like tick frequency and duration, work processed latency, and event loop latency, which provide insights into application performance and potential bottlenecks. These metrics are crucial for understanding application behavior and determining strategies for optimizing performance, such as utilizing all CPUs, tuning the thread pool size, or offloading CPU-intensive tasks to other services. The article highlights the development of a comprehensive event loop monitoring solution by Dynatrace, which plans to integrate event loop telemetry into its root cause detection for enhanced anomaly correlation.