---
id: quartz-cron-checker
version: "0.2.1"
license: unclear
license_treatment: unclear
maintenance: aging
---

# quartz-cron-checker — Simple Python library to check if a Quartz cron expression is valid.

License: unclear · Maintenance: aging · Downloads: 101.3K/mo

## What it is and what it does

quartz-cron-checker is a lightweight validator for Quartz cron expressions in Python. It parses and validates 6- or 7-field cron strings (second, minute, hour, day-of-month, month, day-of-week, and optional year) against the full Quartz specification, including support for special characters like `*`, `?`, `L`, `W`, and `#`, as well as named months and days. It enforces mutual exclusivity between day-of-month and day-of-week fields and provides detailed error messages when validation fails.

The package offers both object-oriented and functional APIs: you can parse a cron string into a QuartzCronChecker object and call validate() on it, or use standalone functions like validate_cron_string() and validate_day_of_month() to check individual fields. It has no runtime dependencies and requires Python 3.10 or later.

Use it for:

- Validate cron expressions before passing them to a Quartz scheduler or job queue system.
- Parse and inspect individual cron fields (second, minute, hour, etc.) for configuration validation.
- Enforce strict Quartz cron syntax in a configuration file or API that accepts cron schedules.
- Catch malformed cron expressions early with detailed error messages during application startup.
- Build a cron expression builder or editor that needs to validate user input against Quartz rules.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Validates Quartz-style cron expressions against the full Quartz specification, including 6- or 7-field formats, special characters, named values, and field-level constraints.

Yes, if you need strict Quartz cron validation and are comfortable with aging maintenance. The package is lightweight, dependency-free, and covers the full Quartz spec including special characters and named values. However, verify the license terms first (currently unclear in metadata) and be aware that no active development is visible—bug fixes or feature updates are unlikely without a maintainer revival.

## Install

pip install quartz-cron-checker
uv add quartz-cron-checker
poetry add quartz-cron-checker

## Installing quartz-cron-checker

Before you install: Low install friction—pure Python wheel with no runtime dependencies. Maintenance status is aging: last release was 442 days ago with no recent commits visible, so expect no active development or rapid bug fixes.

License in practice: License status is unclear—no SPDX identifier or raw license text provided. Before adopting in a commercial or copyleft context, verify the actual license terms from the project source.

Quickstart:

from quartz_cron_checker import QuartzCronChecker, validate_cron_string

# Parse and validate
cron = QuartzCronChecker.from_cron_string("0 0 12 ? * MON-FRI")
cron.validate()  # Raises if invalid

# Or validate directly
result = validate_cron_string("0 0 12 ? * MON-FRI")  # Returns True

Requires Python 3.10 or later.

Verify before relying:

- Whether the project is actively maintained or has been abandoned despite the aging status.
- Actual license terms—SPDX and raw license fields are both null in the metadata.

## Package facts

- License: not declared (unclear)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 101.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

quartz cron validator, cron expression checker, quartz scheduler cron, validate cron strings, cron syntax validation, quartz cron parser, cron field validator, cron-validation, quartz-scheduler, scheduling

[View on SkillFed](https://skillfed.io/packages/quartz-cron-checker) · [View on PyPI](https://pypi.org/project/quartz-cron-checker/)