How to Monitor Node.js Applications in Production (Step-by-Step)

this step-by-step guide, we’ll explore the best practices and tools to monitor Node.js applications efficiently, ensuring optimal performance and quick troubleshooting.

Introduction

Monitoring a Node.js application in production is crucial for ensuring high performance, stability, and reliability. Without proper monitoring, applications may suffer from slow response times, memory leaks, and unexpected crashes, leading to a poor user experience.

Step 1: Identify Key Metrics to Monitor

Before setting up a monitoring solution, it’s essential to define which key performance metrics you need to track. These include:

✅ CPU & Memory Usage – Prevents performance bottlenecks and memory leaks.
✅ Event Loop Lag – Ensures Node.js handles asynchronous tasks efficiently.
✅ Request Throughput & Response Times – Monitors API speed and overall latency.
✅ Error Rates & Logs – Identifies common application errors.
✅ Database Query Performance – Detects slow database operations.
✅ Custom Business Metrics – Tracks specific application events like user signups or transactions.

Step 2: Install a Monitoring Agent

For real-time monitoring, you need to install an agent on your production server. Here’s how to install the Watchlog monitoring agent:

sudo apiKey="your-api-key" server="your-server" bash -c "$(curl -L https://watchlog.io/ubuntu/watchlog-script.sh)"

This script will install the Watchlog agent and start collecting real-time metrics from your Node.js application.

Step 3: Monitor PM2 Applications with Watchlog

The PM2 integration enables real-time monitoring of your PM2-managed applications and sends metrics to the Watchlog Agent for display. With this integration, you can track the status, resource usage, and other key metrics of all your PM2 processes.

Step 1: Clone the PM2 Integration Repository

First, clone the Watchlog PM2 integration repository to your server:

git clone [email protected]:watchlogserver/watchlog-pm2.git

Step 2: Install Dependencies

Navigate into the cloned repository directory and install the necessary dependencies:

cd watchlog-pm2
npm install

Step 3: Start the PM2 Integration with PM2

Once the dependencies are installed, use PM2 to start the integration app. This app will send all PM2 metrics to the Watchlog Agent:

pm2 start watchlog-pm2

Step 4: Verify Integration

After starting the PM2 integration, log in to your Watchlog panel and verify that metrics from your PM2-managed applications are displayed under the PM2 integration section.

Step 4: Integrate Application-Level Monitoring

Using Watchlog-Metric for Custom Events

You can monitor application-specific events (like API request count, active users, or failed transactions) using the watchlog-metric npm package.

Installation:

npm install watchlog-metric

Usage:

const watchlog = require("watchlog-metric");

// Send Metric: Increments a stat by a value (default is 1)
watchlog.increment("api_requests");

// Track custom values
watchlog.increment("failed_logins", 3);

Step 5: Set Up Alerts for Anomalies

To stay ahead of issues, configure alerts for CPU spikes, slow responses, or high error rates.

✅ Slack or Email Alerts: Receive notifications when a threshold is breached. ✅ Webhook Integration: Automate responses when an anomaly is detected. ✅ Custom Alerts: Set up alerts for specific business metrics.

Step 6: Analyze Logs for Deeper Insights

Centralized logging is essential for troubleshooting production issues. You can use tools like Winston, Bunyan, or Watchlog’s built-in logging features.

Example: Winston Logger Integration

const winston = require("winston");
const logger = winston.createLogger({
  level: "info",
  transports: [
    new winston.transports.Console(),
    new winston.transports.File({ filename: "error.log", level: "error" })
  ]
});

logger.info("Application started successfully");
logger.error("Database connection failed");

Step 7: Visualize Metrics with Dashboards

A real-time dashboard helps visualize all collected data. Watchlog provides an intuitive dashboard where you can:

📊 View CPU, memory, and event loop usage. 📊 Analyze API response times and throughput. 📊 Track error rates and anomaly detection reports. 📊 Monitor custom application metrics.

Step 8: Automate Performance Optimization

Once you have collected enough data, use it to optimize your Node.js application:

Optimize database queries to reduce response time.
Improve caching mechanisms for faster API calls.
Scale services dynamically based on traffic spikes.
Refactor slow functions causing performance issues.

Conclusion

Monitoring a Node.js application in production is essential to ensure high availability, performance, and user satisfaction. By following these step-by-step practices, you can proactively detect and fix issues before they impact users.

💡 Start monitoring your Node.js application today with Watchlog and gain full control over your application’s health! 🚀