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Cron expression format rules

Time schedule format for recurring jobs.

Format rules

  • Usually five fields
  • Some platforms add seconds
  • Time zone may be platform-specific

Valid example

0 9 * * 1-5

Invalid example

60 25 * * *

Common errors

  • Assuming Cron expression accepts syntax from a similar format
  • Using the wrong encoding or line ending
  • Copying invisible characters from rich text
  • Testing only the happy path and not parser errors

Online validation and conversion

Compared with nearby formats

Cron expression should be chosen for the parser and ecosystem that will consume it. Prefer strict formats for APIs, human-friendly formats for ops config, and signed formats only when verification is required.