Cron Helper — VS Code Extension

Build, explain, validate, and preview cron schedules right in your editor.

A crontab.guru / crondle alternative inside VS Code. Get instant human-readable descriptions of any cron expression, see upcoming execution times, insert from a library of common schedules, and validate your expressions for potential issues.

Features

🗣️ Explain Any Expression

Type any cron expression and instantly get a plain-English description:

*/5 * * * * → "At minutes 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, and 55 of every hour, every day"
0 9 * * 1-5 → "At 09:00, on Monday through Friday"
0 0 L * * → "At 00:00, on the last day of the month"

⏭️ Next Run Calculator

See the next 10-20 execution times for any cron expression, with relative timestamps (+5m, +2h, +3d).

🧱 Preset Library

Insert common cron schedules with a single click from the Quick Pick menu. Includes 28+ presets:

Every 5/10/15/30 minutes
Hourly, every 2/6/12 hours
Daily at midnight, 9am, twice daily
Weekdays 9am, weekends 10am
Every Monday/Friday
Monthly 1st, quarterly, yearly
Last day of month, 15th nearest weekday
3rd Thursday, last Friday

✂️ Snippets

Type cron- in any YAML or JSON file to get autocomplete snippets for common schedules.

📍 Explain at Cursor (Ctrl+Alt+C)

Place your cursor on a line containing a cron expression and run "Explain at Cursor" — the extension detects the cron pattern automatically.

🔍 Validate with Insights (Pro)

Pro feature — Go beyond basic validation. Get actionable insights about your cron expressions:

OR semantics warnings — catch the #1 cron bug (day-of-month + day-of-week both restricted)
Impossible schedule detection — "Day 31 in February will never run"
Leap year warnings — February 29th only fires in leap years
Step divisor analysis — */7 doesn't divide evenly into 60 minutes
Midnight rush advice — avoid 00:00 scheduling spikes
Frequency estimation — "≈8,760 runs per year" for capacity planning

Usage

Press Ctrl+Shift+P (or Cmd+Shift+P on Mac)
Type "Cron Helper" to see all commands
Or use keyboard shortcuts:
- Ctrl+Alt+C — Explain expression at cursor
- Ctrl+Alt+I — Insert from preset library

Supported Cron Syntax

Syntax	Example	Meaning
`*`	`* * * * *`	Every value (wildcard)
`N`	`5 * * * *`	Single value
`N,M,...`	`1,15,30 * * * *`	List
`N-M`	`0 9-17 * * *`	Range
`*/N`	`/15 * * *`	Step (every N)
`N-M/S`	`1-10/2 * * * *`	Range with step
`JAN-DEC`	`0 0 * JAN-MAR *`	Named months
`SUN-SAT`	`0 0 * * MON-FRI`	Named days
`L`	`0 0 L * *`	Last day of month
`L-N`	`0 0 L-3 * *`	N days before last
`NW`	`0 0 15W * *`	Nearest weekday to N
`D#N`	`0 0 * * 1#3`	Nth weekday of month
`DL`	`0 0 * * 5L`	Last weekday D of month

Configuration

Setting	Default	Description
`cronhelper.defaultRunCount`	`10`	Number of upcoming runs to show
`cronhelper.timezone`	`UTC`	Timezone for run time display

Pro Features

Upgrade to Pro for validation insights (impossible-schedule detection, OR-semantics warnings, frequency estimation, midnight rush advice) — $4/month (or $12/month for teams). Visit https://devforge.dev to get your license key.

Why this extension exists: Every developer writes cron expressions, but cron syntax is error-prone. The top VS Code cron extension has only 66K installs and is unrated. This extension brings the crontab.guru experience directly into your editor, where you write your schedules.

License

MIT

Cron Helper — Expression Builder, Explainer & Validator

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