🚨 Important: Framework support is currently limited to Express. Vitals currently ships with an official adapter for Express only. Support for additional Node.js frameworks is planned.

Vitals collects process health and HTTP metrics, keeps a short rolling history, and provides the monitoring data pipeline used by Vitals integrations.

⚠️ Note: Vitals is designed for live inspection and debugging — not long-term metrics storage or alerting.

📦 @vitalsjs/core

The framework-agnostic metrics engine powering Vitals.

It collects runtime metrics, records HTTP activity, maintains a rolling in-memory history, and streams snapshots through Server-Sent Events.

📥 Installation

npm install @vitalsjs/core

or:

pnpm add @vitalsjs/core

🚀 Quick start

import { VitalsEngine } from "@vitalsjs/core";

const engine = new VitalsEngine({
  sampleIntervalMs: 1000,
}).start();

setInterval(() => {
  const snapshot = engine.getSnapshot();

  if (!snapshot) return;

  console.log({
    cpu: snapshot.cpu.cpuPercent,
    memory: snapshot.memory.heapUsedBytes,
    requests: snapshot.http.requestsPerSecond,
  });
}, 5000);

✨ Features

• 📡 Runtime metrics — CPU, memory, event loop and GC information
• 🌐 HTTP metrics — request throughput, latency and status codes
• 🕰️ Rolling history — short in-memory metric window
• 🔁 SSE broadcasting — stream live snapshots to connected clients
• 🟦 TypeScript-first — complete type definitions included
• ⚡ Low overhead — fixed-cost sampling with allocation-light collectors

🧩 API

VitalsEngine

new VitalsEngine(options?).start();

Main methods:

| Method | Description | | --- | --- | | start() | Starts metric collection | | stop() | Stops collection and closes active streams | | getSnapshot() | Returns the latest metrics snapshot | | getHistory() | Returns rolling metric history | | recordRequest() | Records HTTP request metrics |

📊 Metrics collected

🖥️ Runtime

• CPU usage
• Memory usage
• Event loop delay
• Event loop utilization
• V8 garbage collection pauses

🌐 HTTP

• Request count
• Requests per second
• Latency statistics
• Status codes
• Route aggregation
• Active in-flight requests

🔌 Framework support

@vitalsjs/core is framework-agnostic.

Use it directly with Node.js HTTP servers or through official adapters.

Currently supported:

• Express via @vitalsjs/express

📄 License

MIT © 2026 Ayush Jain