AWS EventBridge
Build AWS EventBridge cron(...) expressions with the ? rule, 1-7 day-of-week, year field, and timezone-aware Scheduler snippets.
Last verified: 2026-05-15
Six fields, including a year
AWS EventBridge (and its successor, EventBridge Scheduler) uses a six-field expression inside a cron(...) wrapper: minute hour day-of-month month day-of-week year. There is no seconds field. The year field is required (use * for all years) and can also be a range like 2026-2030.
The ? rule
Exactly one of day-of-month and day-of-week must be ? — never both, never neither. 0 9 ? * MON-FRI * is valid because day-of-month is ?. 0 9 15 * ? * is valid because day-of-week is ?. 0 9 * * MON-FRI * is rejected at API call time with ValidationException.
Day-of-week 1-7, not 0-6
AWS uses 1 = SUN, 7 = SAT, identical to Quartz and different from Unix. If you have a Unix expression like 0 9 * * 1-5 (weekdays), the AWS equivalent is 0 9 ? * 2-6 * — note the off-by-one in day-of-week and the mandatory ? + year fields.
Rate vs. cron
For simple interval schedules, EventBridge supports rate(5 minutes) in addition to cron(...). Prefer rate(...) when expressing "every N minutes/hours/days" — it's clearer and less error-prone.
EventBridge Scheduler > EventBridge Rules
EventBridge Scheduler (launched late 2022) adds a per-schedule timezone parameter, one-shot schedules, flexible time windows, and dead-letter queues. New work should target Scheduler; classic EventBridge Rules cron is still supported but lacks the timezone field, so cron times are interpreted in UTC.
Found something inaccurate? Let us know via the contact form.