What is a Cron Job?
A cron job is used to schedule tasks that are executed periodically; for example, to send out an email notice every morning, or to clear the cache every so often. Automation of such repetitive tasks using cron jobs saves time and ensures consistency.
Pressable now supports both:
Each option has different use cases and advantages, which are explained below.
WordPress Cron Jobs
In WordPress, the wp-cron function is used to simulate a system cron. The wp-cron() runs a hooked function at a set interval. A backup plugin (like Jetpack Security Daily) runs on a predefined schedule; this is an instance of a WordPress cron job.
An important factor to keep in mind when working with wp-cron: Cron jobs rely entirely on intervals and only work when a page is loaded. In order for wp-cron.php to fire, the website has to be loaded by a visitor; in cases where a website has low traffic, wp-cron.php may not fire often or on time. In this document, we will explain how to work successfully with wp-cron.php. To learn more about WP Cron, we recommend checking out the official WordPress Plugin Handbook.
Server-Side Cron Jobs at Pressable
Pressable now offers platform-managed server-side cron jobs. These are true infrastructure-level scheduled tasks that run independently of website traffic.
Server-side cron jobs:
- Run reliably on schedule
- Do not depend on visitors
- Execute in a secure shell environment
- Support WP-CLI and shell scripts
- Can trigger WordPress cron events
This provides a more reliable alternative to WP-Cron for production workloads.
Managing Server-Side Cron Jobs
This feature is accessible to users with the WordPress management permission enabled:
- Navigate to your site in the Pressable dashboard.
- Scroll down to the Site Tools section of the left navigation menu.
- Within that dropdown, you will see the Cron Jobs section.
- Here, you can view existing cron jobs.
- To create a new cron job, click the Create New button.
- Select a frequency:
- Hourly
- Daily
- Twice Daily
- Weekly
- Enter the command to run.
- Click Create.
Your new cron job will appear in the list. You can use the delete button under the Actions menu to remove it.
If your command contains multiple lines, separate them with semicolons as shown below –
The list will now look as shown below-
Manage Cron Jobs via Pressable API
You also have the ability to list, add, and delete cron jobs in the Pressable API. These endpoints are documented here: https://my.pressable.com/documentation/api#sites-cron-jobs
Additional Notes and Operational Guidelines
Server-side cron jobs operate under the following limits and behaviour guidelines:
- Each cron job can run for up to 8 hours. Jobs that exceed this limit will be skipped automatically.
- If a job is still running when its next scheduled time occurs, the new run will be skipped.
- Up to three cron jobs can run at the same time per site. Additional jobs will be queued and run later.
- Failed jobs are automatically logged and monitored by Pressable systems.
- If cron execution is delayed, missed jobs will run during a catch-up period, but only once per interval. For example, a cron event that was supposed to run once every minute, delayed by 5 minutes, will run only once during the catch-up period, and not five times.
- To run shell scripts stored in your home directory, use a dot-relative path (for example,
./script.sh) or run them withbashorsh. - You may redirect output to a log file using
>>, but log files are not rotated or deleted automatically and will count toward your site’s disk space usage.
WP Cron Jobs at Pressable using a plugin
You can continue to manage WordPress cron jobs on your WordPress site programmatically, using plugins such as Advanced Cron Manager (or a similar plugin like WP Crontrol). These tools allow you to create, edit, and troubleshoot WP-Cron events.
Using Advanced Cron Manager
Once you install and activate the plugin, you should see the Cron Manager under the Tools (or Settings) tab on your WordPress Dashboard.
The Cron Manager allows you to:
- View scheduled events
- Edit or delete jobs
- Run events manually
- Pause or resume tasks
The Execute Now option is useful for troubleshooting.
WordPress provides default schedules such as hourly, daily, twice daily, and weekly. You may also create custom schedules.
Creating Custom WP-Cron Events via Plugin
- Click Add New Event in Cron Manager.
- Enter the event hook and schedule. Create a custom hook and give that hook the name of a function to execute. In the example below, wp_test_email is the hook name and email_cron_function is the function the hook will execute.
- Click Add Event to save.
- Add the corresponding action in your theme or plugin. If your hook is wp_test_email, you’ll need to add this in PHP:
add_action( ‘wp_test_email’, 'email_cron_function' );
function email_cron_function()
{ // This is the task that the cron job will perform when triggered
wp_mail(
'youremail@example.com',
'Automatic email',
'Scheduled email from cron'
); }
Once you become accustomed to their creation, you can create crons to perform tasks for you. Although not essential, having intermediate-level programming and WordPress development skills will make setting up custom crons quick and easy.
Using Monitoring Tools to Trigger wp-cron.php
In order to trigger wp-cron.php without requiring a visit, you can create a monitor in Uptime Robot (or Pingdom) for yoursite.com/wp-cron.php.
Setting up such a monitoring service to visit your site every 5 minutes (or the duration you need) will trigger the wp-cron, and as a bonus, the service will also alert you if the site ever goes down.
Online Cron Services
Alternatively, you may want to look into some of the online cron services to make the process easier. A few such services are listed here:
These are typically unnecessary when using Pressable’s server-side cron feature.
Cron Event Information on Pressable Control Panel
You can now check cron jobs that are running on a site via the Pressable Control Panel. Under the Advanced section, within the Logs menu, the Cron Event Logs are listed. This provides a quick overview of the cron jobs and makes it easy to monitor.
This also includes details like the Hook Name, Next Run Time(GMT and Relative), and Recurrence.
