Node.js, mein, BUILT-IN, --prof, FLAG, se, CPU, PROFILING, ki, ja, sakti, hai — node --prof app.js, EK, LOG, FILE, GENERATE, karta hai, JISE, node --prof-process, se, ANALYZE, kiya, ja, sakta hai.

APM (Application Performance Monitoring) TOOLS — jaise, New Relic, Datadog — PRODUCTION, mein, REAL-TIME, METRICS, (RESPONSE, TIME, ERROR, RATE, THROUGHPUT) TRACK, karte, HAIN, aur, ALERTS, BHEJTE, HAIN, JAB, KUCH, GALAT, HOTA, hai.

// process.memoryUsage() — quick, memory, check:
console.log(process.memoryUsage());
// { rss, heapTotal, heapUsed, external }

// Basic, request, timing, middleware:
app.use((req, res, next) => {
  const start = Date.now();
  res.on("finish", () => {
    console.log(`${req.method} ${req.url} — ${Date.now() - start}ms`);
  });
  next();
});