~/cron-builder

Cron: first of every month at midnight

The cron expression `0 0 1 * *` fires at 00:00 on the 1st day of every month. The `@monthly` macro is the equivalent in most runners.

# expression

0 0 1 * *

Means: At 00:00 on day 1 of every month — 12 fires per year.

→ Open in cron builder (pre-filled)

# common use cases

• Monthly invoicing or billing cycles.
• End-of-month / start-of-month archival jobs.
• Quarterly aggregations (with month restriction: `0 0 1 1,4,7,10 *` = quarter starts).

# next fires (sample)

• Jan 1 00:00
• Feb 1 00:00
• Mar 1 00:00
• Apr 1 00:00
• May 1 00:00

# pitfalls

• On the 1st, many systems run cleanup or rotation at the same instant. Stagger your monthly jobs across the first hour.
• For "last day of month" semantics, POSIX cron has no built-in — use Quartz `L` or schedule on the 1st and check yesterday.

# other patterns

• Cron: every 5 minutes — */5 * * * *
• Cron: every 15 minutes — */15 * * * *
• Cron: every hour — 0 * * * *
• Cron: daily at 3 AM — 0 3 * * *
• Cron: weekdays at 9 AM — 0 9 * * 1-5
• Cron: annually (Jan 1 at midnight) — 0 0 1 1 *

────────────────────────────────────────