Use this topic as a reference for building and validating Quartz-style cron expressions supported by Reltio for scheduling recurring jobs.

Cron expression structure

A cron expression consists of 6 or 7 space-separated fields. Each field represents a time unit and defines the schedule pattern. Reltio uses the Quartz Scheduler format, which differs from traditional UNIX cron by including a seconds field and supporting an optional year field.

┌───────────── second (0–59)
│ ┌───────────── minute (0–59)
│ │ ┌───────────── hour (0–23)
│ │ │ ┌───────────── day of month (1–31)
│ │ │ │ ┌───────────── month (1–12 or JAN–DEC)
│ │ │ │ │ ┌───────────── day of week (1–7 or SUN–SAT, where 1 = Sunday)
│ │ │ │ │ │ ┌───────────── year (optional, 1970–2199)
│ │ │ │ │ │ │
* * * * * * [*]

Field Reference

Each cron expression is composed of multiple fields, where each field represents a specific unit of time such as seconds, minutes, hours, days, etc. The combination of all fields defines when and how often a job runs. The table below lists each field, the valid ranges of values it can take, and the special characters you can use to customize scheduling patterns.

Special Characters

Cron expressions support special characters that provide flexibility beyond simple numeric values. These characters let you define ranges, increments, lists, and special conditions (like the last day of a month or the nearest weekday). They are what make cron expressions powerful, allowing complex schedules to be expressed compactly.

The table below explains the purpose of each special character and how it affects the scheduling logic:

Important rules for writing valid Quartz cron expressions

Example

The following example shows how to construct, validate, and execute a cron expression for the use case: every 15 minutes:

Current time = Wed Aug 13 15:53:45 WEST 2025
Enter values for cron expression:
Seconds (0-59 or *): 0
Minutes (0-59 or *): */15
Hours (0-23 or *): *
Day of a month (1-31, * or ?): *
Month (1-12 or JAN-DEC, *): *
Day of a week (1-7 or SUN-SAT, * or ?): ?
Year (optional, 1970-2199 or *): 
Built expression : 0 */15 * * * ? *
✅ Expression is valid
Child job will start at: Wed Aug 13 16:00:00 WEST 2025
Internal, seconds: 900
Timing of child job 1 = Wed Aug 13 16:15:00 WEST 2025
Timing of child job 2 = Wed Aug 13 16:30:00 WEST 2025
Timing of child job 3 = Wed Aug 13 16:45:00 WEST 2025
Timing of child job 4 = Wed Aug 13 17:00:00 WEST 2025
Timing of child job 5 = Wed Aug 13 17:15:00 WEST 2025

All other common examples of cron expression are summarized below in tabular format for quick reference.