About Cron TimeLock

Cron TimeLock presents two types of challenges: pick the cron expression that matches a plain-English schedule, or spot the bug in a cron that isn't behaving as intended. Every day everyone gets the same challenge so you can compare results. Topics include DOW vs DOM gotcha, timezone confusion, step values, named fields, Quartz extensions, and DST edge cases.

Why it helps

• Build intuition for the most common cron misconfigurations that cause jobs to fire at unexpected times.
• Learn the difference between POSIX 5-field cron, Quartz 6/7-field cron, and macro shortcuts like @daily.
• Use the related Cron Builder to construct your own schedules.

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