node-cron — Task Scheduler for Node.js

What is node-cron?

node-cron is a lightweight library for Node.js that allows you to execute JavaScript functions on a schedule using the cron expression syntax from UNIX systems. It is ideal for automating routine tasks: cache clearing, sending email newsletters, database backups, or server monitoring.

Why do you need a task scheduler?

In web applications, you often need to execute code at a specific time, not just in response to a user request. Instead of using external services (like cron on the server), node-cron works directly inside your Node.js process. This simplifies deployment, does not require configuring a system scheduler, and is ideal for containerized applications (Docker, Kubernetes).

Installation

Installation via npm is done with a single command:

npm install node-cron

After installation, the library is ready to use — no additional dependencies are required.

Main Features

• Flexible scheduling — support for standard cron patterns (minutes, hours, days, months, days of the week).
• Start and stop — each task can be started or stopped on demand.
• Error handling — you can set a callback for logging errors without crashing the application.
• Simple syntax — only two methods: schedule and validate.

Code Example in JavaScript (Node.js)

Let's create a task that prints the current time to the console every minute:

const cron = require('node-cron');

// Task runs every minute: '* * * * *'
cron.schedule('* * * * *', () => {
  console.log('Task executed:', new Date().toLocaleString());
});

console.log('Scheduler started. Press Ctrl+C to exit.');

A more complex example — sending a report every day at 8 AM:

const cron = require('node-cron');

cron.schedule('0 8 * * *', () => {
  console.log('Sending daily report...');
  // Here you call the email sending function
}, {
  scheduled: true,
  timezone: 'Europe/Moscow'
});

Validating a cron expression:

const isValid = cron.validate('*/5 * * * *');
console.log(isValid); // true

When to use node-cron?

• Backup automation — creating a database dump every night.
• Periodic cleanup — deleting outdated sessions or temporary files.
• Monitoring — checking service availability and sending alerts.
• Newsletters — sending emails on a schedule (e.g., digests).
• Cache updates — rebuilding the cache during off-peak hours.

The node-cron library is suitable for projects of any size — from simple scripts to microservice architectures. It requires no external dependencies and works stably even during long uptime.