Crontab expression builder
Build a five-field cron schedule one field at a time — minute, hour,
day of month, month and day of week — or start from a preset like
every 5 minutes or every Monday at 9am. Each field accepts * for any,
lists (1,15), ranges (1-5) and steps (*/5).
The cron expression and a plain-English summary update as you type, and the builder flags out-of-range values. Everything runs in your browser; nothing is uploaded.