Based on my experience in diagnosing and troubleshooting highload e-commerce Node.js app in production, I’ve identified three stages in the Node.js diagnostic history. I’d like to briefly tell this path and show where we are now and tell in details "How to debug and tracing Node.js apps on different levels, and how to track performance problems and memory leaks inside Node.js apps in 2018": Production troubleshooting: I show and explain the strategy of creation and debugging core dump using llnode, node-report and X-Transaction-ID in our company with real-life examples. Memory leaks: I show how to identify memory leaks, memory holders using V8 GC tracing, llnode debugging + gencore tool with real-life examples. Performance: I show how to use 0x flame graph to find performance bottlenecks, how identify Event Loop lags, GC slow work and what can give Async Hooks for that with real-life examples.