# CronWizard

> CronWizard is a free, open-source cron expression generator, validator, explainer, next-run calculator, DST checker, and deployment-configuration toolkit. It supports portable 5-field Unix cron and a documented subset of 6/7-field Quartz cron. Interactive calculations run in the browser and require no account.

Canonical site: https://cronwizard.com/
Primary language: English
Source: https://github.com/musanmaz/cronwizard
Last materially reviewed: 2026-08-05

## Use these pages first

- [Cron Builder](https://cronwizard.com/): Build a Unix or Quartz schedule visually, read its plain-English meaning, preview future runs in an IANA timezone, and generate editable platform configurations.
- [Cron Validator](https://cronwizard.com/advanced): Validate an existing expression, inspect lossless Unix/Quartz equivalents, calculate upcoming runs, and create a fragment-based share link.
- [Cron Expression Library](https://cronwizard.com/cron-expression): Fourteen curated, static expression guides with field breakdowns, DST notes, operational edge cases, and platform conversions.
- [Cron Syntax Documentation](https://cronwizard.com/docs): Unix and Quartz field layouts, ranges, special characters, examples, and FAQs.
- [Cron Dialect Matrix](https://cronwizard.com/cron-dialects): Source-linked comparison of GitHub Actions, AWS EventBridge Scheduler, Vercel Cron Jobs, Spring `@Scheduled`, and systemd timers.
- [Cron DST Checker](https://cronwizard.com/dst): Analyze upcoming timezone-offset transitions and calculated runs around clock changes.
- [API Reference](https://cronwizard.com/docs/api): Human-readable HTTP API documentation and request examples.
- [OpenAPI 3.1](https://cronwizard.com/openapi.json): Machine-readable contract for public API endpoints.

## Platform guides

- [Kubernetes CronJob](https://cronwizard.com/kubernetes): 5-field scheduling, `.spec.timeZone`, concurrency, deadlines, and editable YAML output.
- [GitHub Actions](https://cronwizard.com/github-actions-cron): POSIX schedule syntax, timezone support, five-minute minimum, default-branch behavior, and workflow examples.
- [AWS EventBridge Scheduler](https://cronwizard.com/aws-eventbridge-cron): AWS minute-first six-field grammar, `?`, year, timezone, retries, and delivery controls.
- [Vercel Cron Jobs](https://cronwizard.com/vercel-cron): UTC behavior, plan-dependent cadence, expression restrictions, authentication, and invocation behavior.
- [Spring Cron](https://cronwizard.com/spring-cron): Spring's six-field seconds-first dialect, timezone configuration, overlap, and its differences from Quartz.
- [systemd Timers](https://cronwizard.com/systemd-timer): `OnCalendar` syntax, persistence, accuracy, timezones, and service/timer units.
- [Quartz Cron](https://cronwizard.com/quartz): Quartz-specific seconds, optional year, `?`, supported `L`/`#` cases, and safe conversion limits.

## Product facts and boundaries

- Unix input: exactly 5 fields — minute, hour, day of month, month, day of week.
- Quartz input: 6 required fields plus an optional year. Exactly one of day of month or day of week must be `?`.
- Quartz support: `L` and day-of-week `#` are supported; `W` and hashed/random `H` are rejected. The supported year range is 1970-2099.
- Unix and Quartz are not interchangeable. CronWizard reports `null` / “No lossless equivalent” instead of silently dropping seconds, restricted years, day-of-month `L`, weekday `nL`/`#`, or Unix day-field OR semantics. A bare Quartz weekday `L` means Saturday and is exactly convertible.
- Timezones are not embedded in ordinary cron fields. Next-run results depend on the selected IANA timezone and the target scheduler's runtime policy.
- Export targets: Kubernetes, GitHub Actions, systemd, Docker Compose with Ofelia, AWS EventBridge Scheduler Terraform, crontab, and macOS launchd. The selected IANA timezone is embedded where supported; crontab and launchd deliberately use runtime/host local time. Outputs are editable starting points; target-specific unsupported schedules are rejected rather than approximated.
- CronWizard creates and analyzes schedules. It does not execute, host, monitor, retry, or store users' jobs.
- Share links put the expression after `#`, so it is not included in HTTP requests, server logs, referrers, or analytics page paths.

## Reliability guides

- [Best Practices](https://cronwizard.com/best-practices): Idempotency, locks, retries, observability, security, timezone handling, and missed-run detection.
- [Troubleshooting](https://cronwizard.com/troubleshooting): Diagnose missing, duplicate, delayed, timezone-shifted, or silently failing jobs.
- [Examples](https://cronwizard.com/examples): Quick reusable schedules for common tasks.

## API

- `POST /api/v1/cron/generate` — generate an expression from structured wizard parameters.
- `POST /api/v1/cron/validate` — validate Unix or Quartz syntax; the Unix normalization may be `null`.
- `POST /api/v1/cron/next` — calculate future ISO timestamps and human-readable times in an IANA timezone.
- `POST /api/v1/cron/export` — create a supported target configuration when a lossless 5-field Unix representation exists.
- `GET /api/healthz` — health status.

API endpoints return JSON. Use the [API reference](https://cronwizard.com/docs/api) or [OpenAPI document](https://cronwizard.com/openapi.json) instead of treating POST URLs as human-readable pages.

## Policies and discovery

- [About](https://cronwizard.com/about)
- [Privacy](https://cronwizard.com/privacy)
- [Terms](https://cronwizard.com/terms)
- [Contact](https://cronwizard.com/contact)
- [Expanded LLM Reference](https://cronwizard.com/llms-full.txt)
- [XML Sitemap](https://cronwizard.com/sitemap.xml)
- [Crawler Policy](https://cronwizard.com/robots.txt)

## Optional

- [GitHub Repository](https://github.com/musanmaz/cronwizard): Implementation, revision history, tests, and issue tracker.