*/30 * * * * — what this cron expression means
The cron expression */30 * * * * runs every 30 minutes (on the hour and half past). Here is the field-by-field breakdown and what it means in plain English.
What */30 * * * * means
It runs every 30 minutes (on the hour and half past).
Field by field
minute=*/30 → 0,30; the rest *.
Two runs per hour: at :00 and :30. Identical to writing 0,30 * * * *.
When it runs next
Next runs: the next :00 or :30.
FAQ
What does */30 * * * * mean?
It runs every 30 minutes — at the top of the hour and at half past, every hour of every day.
Is */30 * * * * the same as 0,30 * * * *?
Yes. Both fire at minute 0 and 30. The step form and the list form give the same schedule.