performance_profiling

Run the app with node --prof app.js, then process the log with node --prof-process to get a readable profile. Alternatively, use Clinic.js tools like clinic flame or clinic doctor for visual flamegraphs and automatic bottleneck detection.

Take heap snapshots in Chrome DevTools Memory tab before and after performing actions, then use Comparison view to find growing objects. Filter by Detached to spot DOM leaks, and check common sources like event listeners, timers, and closures.

autocannon is a fast Node.js-based tool run with npx autocannon -c 100 -d 30, while wrk and Apache Bench (ab) offer similar concurrent load testing. Choose based on your environment and scripting needs.

Yes, the React Profiler API and DevTools record render durations per component, and why-did-you-render tracks pure component re-renders. Combine with useMemo, useCallback, and React.memo to eliminate wasted renders.

Use EXPLAIN (ANALYZE, BUFFERS) to see the actual execution plan, row estimates, and buffer usage. Enable pg_stat_statements to rank queries by total time and set log_min_duration_statement to capture slow queries automatically.