> ## Documentation Index > Fetch the complete documentation index at: https://docs.cuey.dev/llms.txt > Use this file to discover all available pages before exploring further. # Cron Expressions > Guide to writing cron expressions for recurring jobs ## Overview Cron expressions define when recurring jobs should execute. Cuey uses the standard 5-field cron format. ## Cron Format Cron expressions consist of 5 fields separated by spaces: ``` ┌───────────── minute (0 - 59) │ ┌───────────── hour (0 - 23) │ │ ┌───────────── day of month (1 - 31) │ │ │ ┌───────────── month (1 - 12) │ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday) │ │ │ │ │ * * * * * ``` ## Field Values | Field | Values | Special Characters | | ------------ | -------------- | ------------------ | | Minute | 0-59 | `*` `,` `-` `/` | | Hour | 0-23 | `*` `,` `-` `/` | | Day of Month | 1-31 | `*` `,` `-` `/` | | Month | 1-12 | `*` `,` `-` `/` | | Day of Week | 0-6 (0=Sunday) | `*` `,` `-` `/` | ## Special Characters * `*` - Matches any value * `,` - Value list separator (e.g., `1,3,5`) * `-` - Range (e.g., `1-5`) * `/` - Step values (e.g., `*/15`) ## Common Examples ### Every Minute ``` * * * * * ``` ### Every Hour ``` 0 * * * * ``` ### Every Day at Midnight ``` 0 0 * * * ``` ### Every Day at 9 AM ``` 0 9 * * * ``` ### Every Monday at 9 AM ``` 0 9 * * 1 ``` ### Every Weekday at 9 AM ``` 0 9 * * 1-5 ``` ### Every 15 Minutes ``` */15 * * * * ``` ### Every 30 Minutes ``` */30 * * * * ``` ### Every Hour on the Hour ``` 0 * * * * ``` ### First Day of Every Month at Midnight ``` 0 0 1 * * ``` ### Every Monday, Wednesday, Friday at 9 AM ``` 0 9 * * 1,3,5 ``` ### Every Day at 9 AM and 5 PM ``` 0 9,17 * * * ``` ## Timezone Support Cron expressions can be combined with timezones to schedule jobs in specific time zones. When creating a cron job, you can specify a timezone (e.g., `America/New_York`, `Europe/London`). If no timezone is specified, UTC is used. ### Example: Daily Report in Different Timezones * **Daily report at 9 AM EST**: `0 9 * * *` with timezone `America/New_York` * **Daily report at 9 AM PST**: `0 9 * * *` with timezone `America/Los_Angeles` * **Daily report at 9 AM UTC**: `0 9 * * *` with no timezone (defaults to UTC) ## Advanced Patterns ### Every 5 Minutes During Business Hours (9 AM - 5 PM, Weekdays) ``` */5 9-17 * * 1-5 ``` ### Every Hour During Night Hours (10 PM - 6 AM) ``` 0 22-23,0-6 * * * ``` ### Twice Daily (9 AM and 6 PM) ``` 0 9,18 * * * ``` ### Every 10 Minutes on Weekdays ``` */10 * * * 1-5 ``` ### First Monday of Every Month This requires more complex logic - consider using scheduled events instead of cron jobs for this pattern. ## Best Practices ### Use Specific Times * ✅ **Good**: `0 9 * * *` - Specific time (9 AM sharp) * ❌ **Avoid**: `* * * * *` - Every minute (unless necessary) ### Consider Timezones * ✅ **Good**: Specify timezone for user-facing schedules (e.g., `America/New_York` for business hours) * ✅ **Good**: Use UTC for system-level jobs (omit timezone or set to `null`) ### Document Complex Expressions When using complex cron expressions, document what they represent in comments or descriptions: * `0 9 * * 1-5` - Weekdays at 9 AM * `*/5 9-17 * * 1-5` - Every 5 minutes during business hours (9 AM - 5 PM, weekdays) ## Common Use Cases ### Health Checks ``` */5 * * * * // Every 5 minutes ``` ### Daily Reports ``` 0 9 * * * // Every day at 9 AM ``` ### Weekly Summaries ``` 0 9 * * 1 // Every Monday at 9 AM ``` ### Monthly Tasks ``` 0 0 1 * * // First day of month at midnight ``` ## Testing Cron Expressions You can test cron expressions using online tools or validate them when creating cron jobs. Invalid cron expressions will be rejected with a validation error. ## Related Resources Understand events and crons. Get started with the TypeScript SDK. Explore the REST API documentation.