Cron Job Every 30 Seconds – How to Achieve Sub-Minute Scheduling
Standard cron's minimum interval is 1 minute. For 30-second intervals, you need two cron entries offset by 30 seconds, or use a dedicated scheduler like CronJobPro that supports sub-minute intervals on higher plans.
How It Works
Standard cron's minimum interval is 1 minute. For 30-second intervals, you need two cron entries offset by 30 seconds, or use a dedicated scheduler like CronJobPro that supports sub-minute intervals on higher plans.
Note: Standard cron only supports minute-level granularity (minimum 1 minute). For sub-minute scheduling, use CronJobPro's Pro plan which supports intervals down to 30 seconds, or set up two cron entries offset by 30 seconds using sleep 30.
Common Use Cases
- Real-time price tracking
- Live dashboard updates
- High-frequency health checks
Schedule This Cron Job Now
Create a free CronJobPro account and use N/A to schedule HTTP requests automatically — with monitoring, retries, and notifications built in.
Frequently Asked Questions
What does N/A mean in cron?
Standard cron's minimum interval is 1 minute. For 30-second intervals, you need two cron entries offset by 30 seconds, or use a dedicated scheduler like CronJobPro that supports sub-minute intervals on higher plans.
How do I use this cron expression?
On Linux/macOS, edit your crontab with crontab -e and add:N/A /path/to/your/script.sh
Or use CronJobPro to schedule HTTP requests with this expression — no server required.
What timezone does cron use?
By default, cron uses the system timezone. CronJobPro lets you set a specific timezone per job, so your schedules are predictable regardless of server location.