Cron Expression Explainer

Cron syntax is write-only. Paste an expression and get it back in English — plus proof, in the form of the next five runs.

minutehourdaymonthweekday

At 09:00 on Monday, Tuesday, Wednesday, Thursday, and Friday.

Next 5 runs (local time)

  • Calculating…

Built with this prompt

Build a cron expression explainer in React with:
- An input for a standard 5-field cron expression (minute hour day-of-month month day-of-week)
- Support for *, ranges, lists, step values (*/15), month/weekday names, and @daily-style aliases
- A plain-English description of the schedule
- The next 5 fire times in the user's local timezone
- Correct semantics: when day-of-month and day-of-week are both restricted, cron ORs them
- Clear inline error messages for invalid fields
- Preset buttons for common schedules
- Dark theme, no dependencies