Cron every 4 minutes: the expression, explained, in Next.js / Vercel
The cron expression for “every 4 minutes” is */4 * * * *. This page shows what each field does, the next five times it will fire, the mistake most people make with it, and a working Next.js / Vercel example you can paste.
The expression
| Field | Value | Meaning |
|---|---|---|
| minute | */4 | every 4 minutes, starting at 0 |
| hour | * | every hour |
| day of month | * | every day of month |
| month | * | every month |
| day of week | * | every day of week |
Next five runs (UTC, from now)
- 2026-09-17 23:00 UTC
- 2026-09-17 23:04 UTC
- 2026-09-17 23:08 UTC
- 2026-09-17 23:12 UTC
- 2026-09-17 23:16 UTC
Mistakes people make with this schedule
- "*/4" means minutes 0, 4, 8… of the hour, not "4 minutes after the last run". The count restarts at the top of every hour, so a run at :05 is impossible with this expression.
- Assuming the server clock is your clock. Cron runs in the machine’s timezone unless the runtime says otherwise; the examples here are UTC.
- No lock around a job that might overlap itself, and no alert when it silently stops. That second one is what Supercrontab is for.
Run it in your stack
// vercel.json
{
"crons": [
{ "path": "/api/cron/run", "schedule": "*/4 * * * *" }
]
}Vercel crons run in UTC and, on the Hobby plan, at most once a day. For anything more frequent call the route from Supercrontab.
Questions
Does */4 * * * * run in my local time?
Only if the scheduler is configured for it. crontab uses the system timezone; Vercel and GitHub Actions always use UTC; Laravel and node-cron take a timezone option. In Supercrontab the timezone is a field on the job.
What if the previous run is still going?
Classic cron starts the next run anyway. Add a lock (flock on Linux, withoutOverlapping() in Laravel) or let Supercrontab skip the tick while the previous request is open.
Is there a shorter way to write this?
No. The five-field form is the shortest portable version.