⏱ Cron Expression Explainer

Explain a 5-field cron expression, preview upcoming local run times, and keep timezone and scheduler dialect caveats visible.

Cron expression

Plain-English description

Next run times

Cron explanation checks

Validates 5-field minute/hour/day/month/weekday syntax, expands lists/ranges/steps, previews next-run candidates, and reports scheduler dialect/timezone risks.

Runs in your browser

Cron explanation runs locally in your browser. Always verify timezone and scheduler dialect before deploying production jobs.

Include current input in shared/debug payload

What this tool does

Cron Expression Explainer turns 5-field cron schedules into plain language and upcoming run previews.

Why it is useful

It helps developers, operators, and agents debug scheduled jobs without guessing how minute, hour, day, month, and weekday fields interact.

How it works

The shared core validates each cron field, expands supported ranges/lists/steps, searches upcoming local run times, and emits typed parser warnings.

Best input

Paste the exact 5-field expression from your scheduler and record the scheduler timezone beside the copied report.

Agent workflow tip

Use the JSON summary when asking an agent to reason about a deployment schedule so the expanded fields and warnings are preserved.

Privacy note

Browser use is local; the API route submits the expression to Utilito's serverless function for automation.

Important limitation

Cron dialects differ. This page does not model Quartz seconds/year fields, every named alias, or scheduler-specific day-of-month/day-of-week semantics.

Quick answers

Why are the next runs local time?

The browser preview starts from the current local time. Production schedulers may use UTC, account, project, or configured timezones.

Does this support Quartz cron?

No. It focuses on practical 5-field cron and warns when scheduler dialects may differ.

Common Use Cases

Review a deployment job

Check that a weekday CI or backup schedule runs during the intended window.

Explain a crontab to a teammate

Copy the plain-English description and warnings into an issue or runbook.

Give agents schedule context

Copy the JSON summary so an agent can reason about next runs without reparsing the expression.

API examples

Call the same deterministic core through Utilito’s compact API router. Send only data you intentionally submit to the server-side endpoint.

Try in API playground →Schema →

Explain a cron expression with curl

curl

curl -X POST https://utilito.dev/api/run \
  -H "Content-Type: application/json" \
  -d '{"tool_id":"cron-expression-explainer","input":{"expression":"*/15 9-17 * * 1-5","count":5}}'

Explain a cron expression from JavaScript

javascript

const res = await fetch('https://utilito.dev/api/run', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    tool_id: 'cron-expression-explainer',
    input: { expression: '*/15 9-17 * * 1-5', count: 5 }
  })
});
const data = await res.json();
console.log(data.result.output || data.result.report);

Explain a cron expression from Python

python

import requests
payload = {
    "tool_id": "cron-expression-explainer",
    "input": {"expression": "*/15 9-17 * * 1-5", "count": 5},
}
result = requests.post("https://utilito.dev/api/run", json=payload).json()["result"]
print(result.get("output") or result.get("report"))

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