Cron

cron_schedules is the only way to add a custom recurring interval — WordPress ships with hourly, twicedaily, and daily only.

Signature

Example

add_filter( 'cron_schedules', function( $schedules ) {
    $schedules['every_fifteen_minutes'] = [
        'interval' => 15 * MINUTE_IN_SECONDS,
        'display'  => 'Every 15 Minutes',
    ];
    return $schedules;
} );

Common Use Cases

• Add a custom recurring interval (e.g. every 15 minutes)
• Register a weekly or non-standard interval
• Match a plugin's own scheduled task frequency
• Support finer-grained sync/polling than core's daily/hourly options

cron_request controls the loopback HTTP request WordPress fires to trigger wp-cron.php in the background — the standard hook for disabling that self-ping when cron is driven by a real system cron job instead.

Signature

Example

add_filter( 'cron_request', function( $request ) {
    error_log( 'Cron spawn request: ' . $request['url'] );
    return $request;
} );

Common Use Cases

• Extend the timeout for slow-running cron jobs
• Add authentication headers to the internal cron request
• Log or monitor cron-spawn activity
• Redirect the request when cron runs behind a load balancer or proxy

wp_scheduled_delete runs once a day as a scheduled WP-Cron event, immediately before WordPress permanently deletes posts that have sat in Trash longer than EMPTY_TRASH_DAYS.

Signature

Example

add_action( 'wp_scheduled_delete', function() {
    error_log( 'Trash cleanup cron run started.' );
} );

Common Use Cases

• Piggyback custom database cleanup on the daily cron cycle
• Log or monitor trash-purge activity
• Audit how much content is being auto-deleted
• Trigger a backup before old content is purged