---
id: cron-validator
version: "1.0.8"
license: MIT
license_treatment: permissive
maintenance: abandoned
---

# cron-validator — Unix cron implementation by Python

License: permissive · Maintenance: abandoned · Downloads: 1.5M/mo

## What it is and what it does

Cron Validator is a Python library for working with Unix cron expressions. It parses and validates cron syntax, tests whether a cron schedule matches a given datetime, generates all execution times matching a cron expression within a date range, and provides a simple scheduler loop for triggering tasks on cron intervals. The package also supports a subset of AWS EventBridge extended cron syntax (the 'L' and 'W' operators for day-of-month and day-of-week fields).

The library depends on python-dateutil and pytz for datetime handling and timezone support. It is a straightforward, single-purpose tool with no external system dependencies—install via pip and import CronValidator or CronScheduler to start using it. The project has been abandoned since June 2023, so it receives no active maintenance.

Use it for:

- Validate user-supplied cron expressions before storing or executing them in an application.
- Find all times a cron schedule will fire between two dates for reporting or audit purposes.
- Build a simple in-process task scheduler that runs callbacks on cron-defined intervals.
- Test whether a specific datetime matches a cron expression in unit tests or data pipelines.
- Parse and work with cron schedules in applications that need to integrate with cron-based workflows.

## Worth the install?

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

Validates Unix cron expressions, matches them against specific datetimes, generates execution times within a date range, and provides a scheduler for running tasks on cron schedules.

Yes, if you need lightweight cron expression parsing and scheduling in a Python application and can accept an unmaintained library. The low install friction, permissive license, and zero known vulnerabilities make it a low-risk choice for non-critical scheduling tasks. No, if you require active maintenance, ongoing bug fixes, or support for the full breadth of cron syntax variants.

## Install

pip install cron-validator
uv add cron-validator
poetry add cron-validator

## Installing cron-validator

Before you install: Low friction: pure Python wheel with only two lightweight runtime dependencies (python-dateutil and pytz). Maintenance status is abandoned as of June 2023 with no recent updates, so expect no bug fixes or feature work going forward.

License in practice: MIT license is permissive, allowing commercial and private use with minimal restrictions—suitable for most projects that can accept an unmaintained dependency.

Quickstart:

pip install cron-validator

from cron_validator import CronValidator

assert CronValidator.parse('* * * * *') is not None
assert CronValidator.parse('*/61 * * * *') is None

Verify before relying:

- Whether the package handles all edge cases in cron syntax or only a subset of standard Unix cron rules.
- Performance characteristics when generating execution times across large date ranges.
- Compatibility with Python versions not explicitly declared in the package metadata.

## Package facts

- License: MIT (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: abandoned
- Downloads: 1.5M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

cron expression validator, cron scheduler python, unix cron parser, cron job timing, cron expression matcher, schedule tasks by cron, cron execution times, scheduling, cron, task-automation

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