Cron Expression Builder
Build and validate cron expressions with plain-English descriptions, next-run previews and an optional seconds field. Also available as a REST API.
Cron Expression Builder
At 9:00 AM, Monday through Friday
09*Every day of month (1-31)
*Every month (1-12)
1-5Next 5 executions
Cron field reference
0-59
0-23
1-31
1-12 (1=Jan)
0-6 (0 or 7=Sun)
* any value, value list- range/ step valuesHave an expression already? Test it with our Cron Expression Tester to see next run times and convert natural language to cron.
Updated . Provided as is. Check the output before you rely on it in production.
How to use Cron Expression Builder
- 1
Pick a preset or start from scratch
Open the Presets dropdown for common schedules like every 5 minutes, daily at midnight, or weekdays at 9 AM. The expression updates instantly.
- 2
Set each field's mode
Each field (minute, hour, day, month, weekday) offers Every, Specific, Range, and Step modes. Pick values to build the exact schedule you need.
- 3
See the cron expression preview
The cron syntax (e.g., `0 9 * * 1-5` for 9 AM weekdays) and a plain-English description update in real time as you edit the fields.
- 4
Copy cron expression
Click 'Copy' to copy the expression to your clipboard. Paste into crontab, GitHub Actions, AWS CloudWatch, or any scheduler that uses cron syntax.
- 5
Check the next run times
The 'Next 5 Executions' list updates automatically with upcoming run times in local time, so you can confirm the schedule before deploying.
Questions and answers
What is Cron Expression Builder?
What cron format does it support?
REST API
Base URL
https://aidevhub.io/api/cron-expression/ No authentication, fair use. Abusive traffic is throttled at the edge; responses carry no quota headers. CORS enabled. OpenAPI spec
Endpoints
Example
curl "https://aidevhub.io/api/cron-expression/parse/?expression=0+9+*+*+1-5"
Example Response
{
"valid": true,
"expression": "0 9 * * 1-5",
"human": "At 09:00, Monday through Friday"
} For AI agents: how to call this tool
Machine-readable contract, endpoints and examples. Humans can ignore this section.
Best Path For Builders
Dedicated API endpoint
Deterministic outputs, machine-safe contracts, and production-ready examples.
Dedicated API
https://aidevhub.io/api/cron-expression/build/ OpenAPI: https://aidevhub.io/api/openapi.yaml