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How do you monitor a Node.js application's memory usage in production?

Q: How do you monitor a Node.js application's memory usage in production?

**TL;DR.** Continuously track process.memoryUsage() (**RSS**, **heapUsed**, **external**, **arrayBuffers**) and **event-loop lag**, export them as **metrics** (Prometheus) and dashboards/alerts. Watch for steadily **rising heap** (leak) or RSS near the container limit (OOM-kill risk), and capture snapshots on alert. app /metrics memoryUsage() Prometheus scrape + store <path class='d-

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Expose memory metrics for Prometheus

import client from 'prom-client';
client.collectDefaultMetrics();      // includes process_resident_memory_bytes, heap, GC

const heap = new client.Gauge({ name: 'app_heap_used_bytes', help: 'heap used' });
setInterval(() => heap.set(process.memoryUsage().heapUsed), 5000);

app.get('/metrics', async (_req, res) => res.end(await client.register.metrics()));

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