Cron every 3 minutes

Because the sequence starts at :00 and advances by three: :00, :03, …, :57. It produces 20 runs per hour, and the :57-to-next-:00 gap is exactly three minutes. Expression: */3 * * * *

Use 1-59/3 * * * *. It fires at :01, :04, :07, and every third minute through :58. Expression: 1-59/3 * * * *

Use */3 9-17 * * 1-5. Because 9-17 is inclusive, the cadence continues through 17:57 on weekdays. Expression: */3 9-17 * * 1-5

At best it checks immediately; at worst a change waits almost three minutes, plus queue and execution delay. Use this cadence only when that bound justifies 480 daily runs.

Use */3 * * * 1-5. The day-of-week restriction pauses the schedule on Saturday and Sunday without changing the minute alignment. Expression: */3 * * * 1-5

Behaviour depends on the scheduler. Vixie/cronie can skip or double local matches; GitHub advances nonexistent local times; EventBridge Scheduler skips spring and runs once in the fall overlap. UTC-only Vercel and Cloudflare keep the three-minute cadence unchanged.

No. GitHub Actions scheduled workflows have a five-minute floor; */5 * * * * is the nearest supported slower cadence. EventBridge's one-minute floor permits every three minutes. Expression: */5 * * * *

Use cron(0/3 * * * ? *). EventBridge includes a year field, requires ? in one day field, and wraps the six fields in cron(...). Expression: 0/3 * * * ? *

Use 0 0/3 * * * ?. Quartz reads the leading 0 as seconds and starts the minute step at minute zero. Expression: 0 0/3 * * * ?

Use a persisted high-water mark and query from that mark through the current run time. Cron does not replay a missed slot, so fixed three-minute wall-clock windows can lose data after downtime.

This schedule makes 480 calls per day, so check API quotas, execution cost, and overlap risk. Crontap can run it with retries when a scheduled HTTP request fails.

*/3 * * * *. Paste this into Linux crontab, Vercel cron, node-cron, robfig/cron, or a Kubernetes CronJob to run a job every 3 minutes; AWS EventBridge and Quartz need the six-field form.

The editor above shows the next 30+ runs on a calendar in your local timezone, plus a plain-English description. If the calendar matches your intent, the cron is correct.

Linux crontab, Vercel cron jobs, node-cron, robfig/cron, and Kubernetes CronJob accept the five-field form as is. AWS EventBridge and Quartz use six-field expressions with a ? in one of the day fields; see the AWS and Quartz guides for the conversion. Vercel's free Hobby plan caps the minimum frequency at once-per-day; the Pro plan removes that cap.

Most schedulers will start the new run anyway, leading to overlap. To prevent this, wrap the command with flock -n /tmp/myjob.lock /path/to/script.sh on Linux, or set concurrencyPolicy: Forbid on Kubernetes CronJob. Vercel and EventBridge may overlap runs if the previous one is still executing; make the handler idempotent.