* Reference Guide · 4 Dialects
Cron
Dialects.
Cron expressions behave differently across environments. Explore the definitive field reference, special characters, and syntax for the world's most popular schedulers.
AWS
AWS EventBridge
AWS EventBridge (formerly CloudWatch Events) supports two expression formats: cron() for calendar-based schedules and rate() for simple recurring intervals.
Jenkins
Jenkins Pipeline Cron
Jenkins extends the standard 5-field cron syntax with the H (hash) symbol, which distributes scheduled jobs across available time slots based on a hash of the job name.
Quartz
Quartz Scheduler
Quartz Scheduler is the dominant Java job scheduling library, and its cron dialect extends standard 5-field syntax with a seconds field at position 1, an optional year field at position 7, and a rich set of special characters — L (last), W (nearest weekday), and # (Nth weekday).
Standard
Standard
The standard 5-field cron format is the original Unix scheduling syntax, supported natively by crontab on Linux, macOS, and most Unix-like systems.
* At a Glance
Dialect Comparison
| Feature | Standard | Quartz | Jenkins | AWS |
|---|---|---|---|---|
| Field count | 5 | 6–7 | 5 | 6 |
| Seconds field | — | Required (1st) | — | — |
| Year field | — | Optional (7th) | — | Required (6th) |
| ? (DOM/DOW) | Some impls | ✓ Required | — | ✓ Required |
| L (last) | Some impls | ✓ | — | ✓ |
| # (nth weekday) | — | ✓ | — | — |
| H (hashed) | — | — | ✓ | — |
| W (nearest weekday) | Some impls | ✓ | — | ✓ |
The Wildcard
Matches everything.
The asterisk is the most fundamental cron operator — it means "every". Every minute, every hour, every day. It's the symbol we built this site around.