What does the cron expression */15 * * * * mean?

The cron expression */15 * * * * schedules a job to run every 15 Minutes. The five fields represent: minute, hour, day of month, month, and day of week.

How do I schedule a cron job to run every 15 Minutes?

Add this line to your crontab: */15 * * * * /path/to/command. Open your crontab for editing with crontab -e and paste the expression followed by your command.

How do I monitor a cron job that runs every 15 Minutes?

Add a heartbeat check: */15 * * * * /path/to/script.sh && curl -fsS https://cronsignal.io/ping/YOUR_CHECK_ID. You'll be alerted if the job doesn't run on schedule.

Cron Every 15 Minutes

Understanding the Expression

The cron expression */15 * * * * breaks down as follows:

Field	Value	Meaning
Minute	*/15	Every 15 minutes
Hour	*	Every hour
Day of month	*	Every day of the month
Month	*	Every month
Day of week	*	Every day of the week

Example Usage

Basic crontab entry

*/15 * * * * /path/to/your/script.sh

With output logging

*/15 * * * * /path/to/script.sh >> /var/log/script.log 2>&1

With monitoring

*/15 * * * * /path/to/script.sh && curl -fsS https://cronsignal.io/ping/YOUR_CHECK_ID

Common Use Cases for Every 15 Minutes

Real-time monitoring: Check system health and service availability
Queue processing: Process background job queues frequently
Cache warming: Keep caches fresh with regular updates
Metrics collection: Gather application and infrastructure metrics

Platform Equivalents

The same schedule expressed across common platforms and schedulers:

Platform	Syntax
Linux crontab	`/15 * * *`
GitHub Actions	`- cron: '/15 * * *'`
systemd timer	`OnCalendar=*:0/15`
Kubernetes CronJob	`schedule: "/15 * * *"`
AWS EventBridge	`cron(0/15 * * * ? *)`

Timezone Considerations

Fires at :00, :15, :30, :45 of every hour — 96 times per day. Timezone-independent.

Common Mistakes

Overlaps with other schedules: Fires at minute 0, overlapping with */30 and hourly jobs. Watch for resource contention.
Kubernetes concurrency: If a run takes over 15 minutes, the next run queues up. Set concurrencyPolicy: Forbid to prevent overlap.
AWS EventBridge: cron(0/15 * * * ? *) — uses 0/15 step notation.