Conflict Detector

Paste multiple cron expressions to find scheduling conflicts and overlapping run times.

Compare & Detect Conflicts

Enter a second cron expression to check for execution overlaps within a 24-hour window.

How to use the Conflict Detector

Two jobs that start in the same minute compete for CPU, database connections and locks. Backups, report builds and cache warmers often end up stacked at the top of the hour because everyone picks round numbers.

The Conflict Detector expands two cron expressions over a 24-hour window starting at midnight in your browser time zone, then marks every minute where both fire. The timeline shows each schedule and the overlaps, and the risk badge sums them up: none, low, or high when the overlaps repeat throughout the day.

Step by step

  1. Enter your first expression as the primary schedule.
  2. Enter a second expression that runs on the same machine, database or queue.
  3. Run the check and read the overlap times and the risk level.
  4. If there are overlaps, move one job by a few minutes and check again.

Examples

*/10 * * * * and */15 * * * *
High risk: 48 overlaps a day, at :00 and :30 of every hour
Offsetting the second job to 2-59/15 (minutes 2, 17, 32 and 47) removes every overlap.
0 2 * * * and 30 2 * * *
No overlap
Thirty minutes apart is fine as long as the first job finishes in under half an hour.
0 2 * * * and 0 2 * * *
Low risk: 1 overlap at 02:00
Identical schedules always collide. Stagger them, or run them in sequence from one job.

Things to watch for

  • The detector compares start minutes only. A job that runs for 20 minutes can still collide with one that starts 10 minutes later.
  • Weekly or monthly schedules may show no overlap today but collide on another day. Check them against the day they actually run.