What are cron jobs and what can you do with them?

This may sound niche, but cron jobs are pretty important when it comes to maintaining a website. They're valuable for system administrators and developers to streamline workflows.

But what exactly are they? Why do they matter for managing a website? And how can you put them to work for you (without needing a PhD in DevOps)? Let’s dig into the world of automated website tasks—and how they quietly keep the internet humming along.

What are cron jobs and scheduled tasks?

At their core, cron jobs and scheduled tasks are just instructions for your server to do something automatically at a specific time or interval.

Think of them like setting an alarm clock for your website—but instead of waking you up, the alarm tells your site to run a script, check for updates, back something up, or clean up temporary files.

A cron job (short for “chronograph job”) is the term commonly used in Unix-like systems (Linux, macOS, etc.). On Windows, the same concept is often called a scheduled task. Different systems, same idea: doing stuff automatically on a recurring basis.

Why are cron jobs useful for websites?

If your website has even a smidge of complexity, chances are cron jobs are doing something important in the background. They can:

• Automate database backups
• Clear expired sessions or cache files
• Send out scheduled emails or notifications
• Import new data from an API
• Generate reports
• Update sitemaps or ping search engines

Basically, they take repetitive or time-sensitive tasks off your plate—and make sure they happen reliably at the right time. Real-world examples of cron jobs in action

So what does this look like in the wild? Here are some everyday examples:

Automatically back up your database

Let’s say you run an online store. You don’t want to manually back up your database every day (you won’t remember). A cron job can run every night at 2:00 AM and store a backup copy safely in the cloud. This can look something like:

0 2 * * * /usr/bin/mysqldump -u youruser -pYourPassword dbname > /backups/db_backup.sql

It looks like an alien language but it's extremely helpful.

Send weekly newsletters or reminders

You’ve got a script that compiles your content and sends it to subscribers every Friday at noon? Cron job it. Not that you necessarily should—I mean, marketing automation tools exist—but you could if you wanted to!

Clean up expired shopping carts

If your website stores temporary carts or session data, you might not want that clutter building up forever. A scheduled task can run every hour to remove old entries and keep things tidy.

Run analytics reports

Let’s say you’ve got a script that crunches traffic stats and emails a report to your team. Schedule it to run once a week, and boom—instant, hands-free insight.

How are cron jobs configured?

Cron jobs live in what’s called a crontab file (short for "cron table"). It’s basically a list of Linux commands paired with scheduling instructions. Here's what a line in a crontab might look like:

30 3 * * 1 /home/user/scripts/weekly_backup.sh

This would run the weekly_backup.sh script every Monday at 3:30 AM.

The five numbers represent:

minute (0 - 59)
hour (0 - 23)
day of month (1 - 31)
month (1 - 12)
day of week (0 - 6) (Sunday to Saturday)

For Windows-based hosting, Task Scheduler provides a graphical interface instead of a text file, but the concept remains the same. How to check if your cron jobs are running properly

Here’s where it gets interesting (and often overlooked): setting up a cron job is easy. Knowing it’s still working after a month? Not so easy.

A common problem is what we call the “silent fail.” Something breaks—an API goes offline, a path changes, a server permission is updated—and your script just… stops running. No alert, no red blinking lights. You only notice when data’s missing, emails stop sending, or backups haven’t happened in weeks.

You might never know unless you log cron job output somewhere or you have some sort of monitoring solution in place.

Why monitoring your cron jobs matters

You don’t want to rely on good luck and vague assumptions. That rarely ends well.

Cron jobs are often responsible for essential functions—like backups, maintenance, and syncing external data. If they stop working, the results can range from mildly annoying (missing newsletter) to business-crippling (database wasn’t backed up before a crash).

That's why monitoring these things matter. But how? Well, lucky for you you're already at the right place! As a full-fledged website monitoring solution, Oh Dear also allows you to monitor cron jobs and scheduled tasks.

With a monitoring tool in place, you can get an alert if:

• A cron job doesn't run on time
• A job fails to complete
• The output contains unexpected errors

That way, you catch problems early before your customers (or boss) do.

Pro tips for managing cron jobs

Want to run a tight ship? Here are a few tips to keep your scheduled tasks healthy and reliable:

1. Log output from each job, especially if it interacts with external APIs.
2. Use cron expressions wisely, test your timing and make sure you don’t overload your server.
3. Avoid overlapping jobs since some tasks need to complete before another starts.
4. Document what each job does so you (or future you) can remember why it’s running.
5. Use a centralized monitoring tool so you don’t have to check logs manually.

When to use cron jobs

While cron jobs are powerful, they’re not always the right tool for everything. If you need to run jobs triggered by user actions (I.E. processing image uploads, sending welcome emails), consider using a background job queue instead (like Laravel Horizon, Sidekiq, or Celery). Or use a dedicated tool instead, of course.

Cron jobs are great for predictable, recurring jobs. Background workers are better for event-driven workflows. And if you ever sense you're losing track of them, Oh Dear is here to help you stay on top of things.

Peace of mind is the best thing we can offer you. Your first 30 days of peace of mind are on us, by the way.