Cron syntax is compact, unforgiving, and easy to get wrong in ways that only show up a month later.
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Cron Expression Generator
Minute
Hour
Day of month
Month
Day of week
Free · API · MCPToolYour platform
Use Cron Expression Generator three ways
The free Cron Expression Generator on this page works in your browser. The same workflow is available via REST API for apps and via MCP for Cursor, Claude, and other agents — one API key, one plan, one quota. This tool is part of the developer-apis module under Developer Tools.
- Free in browserUse Cron Expression Generator here — no account required.
- REST APICall from your server with
X-Api-Key. - MCP for agentsConnect Cursor or Claude to ToolYour MCP with the same key.
- 1. Get an API keySign in and open Dashboard → API Keys (works for REST and MCP).
- 2. Call or connectUse the REST API from your server, or paste the MCP URL into your agent config.
- 3. Same qualityOutput matches the free web tool across all three surfaces.
What is Cron Expression Generator?
Cron syntax is compact, unforgiving, and easy to get wrong in ways that only show up a month later. This cron expression generator assembles the five standard fields — minute, hour, day of month, month, and day of week — into a valid expression and, more usefully, computes the next five times it will actually fire in UTC so you can check the schedule against your intention.
That preview is the real safeguard. It catches the classic mistake of setting the hour but leaving the minute as a wildcard, which produces sixty runs an hour instead of one. Fields default to a wildcard when omitted. Scope is the classic five-field format: no Quartz seconds field, no AWS EventBridge day-of-week quirks, and no timezone calendar, so next runs are UTC and mapping to a scheduler's local zone is on you. To check an expression you already have, Cron Expression Parser does the reverse.
Browser use is free and needs no signup. The same job runs over REST at POST https://api.toolyour.com/api/v1/developer-apis/cron-expression-generator and over MCP at https://api.toolyour.com/mcp — one API key, one shared monthly credit pool, 1 credit per successful call.
What are common questions about Cron Expression Generator?
Five fields or six?
Five — minute, hour, day of month, month, and day of week. Quartz-style seconds fields are not part of this format.
Which timezone are the previewed runs in?
UTC. If your scheduler runs in a local zone, convert the times before deciding the schedule is correct.
What happens if I leave a field blank?
It defaults to a wildcard, meaning every value. That is why leaving the minute blank produces an hourly-looking schedule that actually runs every minute.
What are the key features of Cron Expression Generator?
Field-by-field construction
Build the expression from named fields instead of counting positions in a string.
Next five runs previewed
Concrete UTC timestamps confirm the schedule means what you intended.
Invalid input rejected
An expression the parser cannot read fails with an error rather than a silent default.
How do you use Cron Expression Generator?
Set the fields
Fill in the values you care about; the rest default to wildcards.
Check the previewed runs
Confirm the frequency and the times match what you meant.
Deploy and confirm
Copy the expression into your scheduler and verify its own next-run display agrees.
The cron mistakes that cost the most
**Wildcard minutes** —
* 3 * * * looks like three in the morning and runs sixty times between three and four. Setting the minute explicitly is the single highest-value habit in cron.
**Day-of-month and day-of-week together** — when both are restricted, standard cron treats them as OR, not AND, so a job set for the first of the month and Monday runs on both. **Timezone assumptions** — a container scheduler running UTC will not respect the local time you had in mind, and daylight-saving transitions make some local times occur twice or not at all. **Overlapping runs** — a five-minute schedule for a job that sometimes takes seven minutes needs a lock, which cron itself will not provide.Building and verifying schedules
Use this tool when you are designing a schedule from intent, and Cron Expression Parser when you have inherited an expression and need to know what it does. Both report UTC, so run the target times through Timestamp Converter if your team thinks in a local zone.
One caution about platform differences: Kubernetes CronJob, AWS EventBridge, GitHub Actions, and traditional crontab all accept expressions that look identical but differ around day-of-week numbering and extra fields. Always confirm against the next-run display of the platform that will actually run the job.
Which formatter and utility tools sit in this cluster?
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Build UTM links, check ads copy limits, QA email subjects, and calculate ROAS/CPC/CTR — free in the browser; R
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