Free tool
Cron expression generator
Standard cron or Quartz — build it with dropdowns or paste one, and see what it means in plain English and exactly when it runs next.
Build your schedule
Fields: minute hour day-of-month month day-of-week
This schedule runs
—
Next runs (your local time)
Cron jobs fail silently. Spectra doesn't.
Add one line to your job and Spectra's heartbeat monitoring alerts you the moment a scheduled run is missed — before a broken backup becomes a crisis. Free forever, no credit card.
Frequently Asked Questions
Answers to common questions teams ask us
What is a cron expression?
A cron expression is a schedule made of fields — minute, hour, day of month, month, and day of week (standard cron) — used by cron and most schedulers to decide when a job runs. For example, 0 9 * * 1-5 means 9:00 AM every weekday.
What's the difference between standard cron and Quartz?
Standard (Unix) cron uses 5 fields and numbers days of the week 0–6 (Sunday = 0). Quartz — used by Java schedulers like Spring — uses 6 or 7 fields: it adds a leading seconds field and an optional trailing year, numbers days of the week 1–7 (Sunday = 1), and uses '?' in the day-of-month or day-of-week field. Use the toggle to switch parsers.
How do I build a cron expression?
In Standard mode, use the builder: for each field pick a mode — every value, every N, specific value(s), or a range — and the expression is generated for you. In either mode you can pick a preset or type an expression directly to see it explained and previewed.
Why should I monitor my cron jobs?
Cron jobs fail silently — a backup or sync can stop running for days before anyone notices. Heartbeat monitoring alerts you when a job doesn't check in on schedule, so a missed run becomes an alert instead of a surprise.
