How It Works

This tool generates CRON expressions from a simple point-and-click interface — entirely inside your browser. No data is sent to a server.

What is a CRON Expression?

A CRON expression is a string of five fields separated by spaces that defines a recurring schedule for a job scheduler (cron daemon on Unix, GitHub Actions, AWS EventBridge, etc.). Each field controls one dimension of time:

An asterisk (*) in a field means "every valid value for that field." For example, 0 9 * * 1 means "at 09:00 every Monday."

Implementation Details

The generator is written in plain JavaScript. When you click Generate, the selected frequency and time values are read from the form controls and assembled into a five-field CRON string using simple string concatenation. A human-readable description and a field-by-field reference table are then rendered directly in the page without any page reload.

All scheduling logic runs in the browser — no network requests, no backend, no libraries. Time values (hours) follow UTC unless your scheduler interprets them otherwise.

Common Examples

Privacy

Everything runs locally in your browser. No schedule data is transmitted anywhere.