Performance Profiling Find where your application actually spends time before touching a line of code. Covers the full stack: Node.js CPU and memory profiling, browser flame graphs, React render profiling, and database query analysis. The discipline here is profile first, optimize second — premature optimization is not a workflow, it is a guess. When to Use Use for : - Diagnosing slow Node.js applications (CPU-bound, I/O-bound, memory pressure) - Generating and reading flame graphs to find hot code paths - Detecting memory leaks via heap snapshots and growth trends - Profiling React component…