---
id: aws-cron-expression-validator
version: "1.1.15"
license: unclear
license_treatment: permissive
maintenance: active
---

# aws-cron-expression-validator — ValidatesAWS EventBridge cron expressions, which are similar to, but not compatible with Unix style cron expressions

License: permissive · Maintenance: active · Downloads: 81.1K/mo

## What it is and what it does

This package validates cron expressions in the format used by AWS EventBridge, which differs from standard Unix cron in field count (six instead of five), range constraints, and wildcard support. EventBridge cron expressions use minute, hour, day-of-month, month, day-of-week, and year fields, with wildcards including *, /, -, and , plus special operators like L, W, and # for day-of-month and day-of-week fields.

The validator raises specific exceptions (e.g., AWSCronExpressionMinuteError) for invalid fields and generic ValueError for malformed expressions. It has no runtime dependencies and requires Python 3.10 or later. The package is small, actively maintained, and suitable for applications that need to validate EventBridge schedules before submission or for testing scheduling logic.

Use it for:

- Validate cron expressions before deploying EventBridge rules to catch syntax errors early.
- Build a CLI tool or web form that accepts cron schedules and rejects invalid AWS expressions.
- Test event scheduling logic in unit tests by validating expressions your application generates.
- Migrate Unix cron jobs to AWS EventBridge with confidence that expressions conform to AWS syntax.

## Worth the install?

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

Validates AWS EventBridge cron expressions, which use a six-field format with wildcards and constraints that differ from Unix cron syntax.

Yes. If you work with AWS EventBridge schedules, this lightweight validator saves debugging time by catching expression errors before deployment. No dependencies, permissive license, active maintenance, and a clear API make it a low-risk addition to projects that need cron validation.

## Install

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

## Installing aws-cron-expression-validator

Before you install: Low friction: pure Python, no runtime dependencies, distributed as a wheel. Actively maintained with recent releases; last commit 2026-04-14.

License in practice: MIT license (permissive); you can use, modify, and distribute this package freely in commercial and private projects.

Quickstart:

pip install aws-cron-expression-validator

from aws_cron_expression_validator.validator import AWSCronExpressionValidator

AWSCronExpressionValidator.validate("0 180 ? * MON-FRI *")

Requires Python 3.10 or later.

Verify before relying:

- Whether the validator catches all edge cases in AWS's wildcard semantics (L, W, # operators for day-of-month and day-of-week fields).
- Performance characteristics when validating large batches of expressions.

## Package facts

- License: not declared (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 81.1K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

aws eventbridge cron validation, validate cron expressions, aws cron expression parser, eventbridge schedule validator, cron syntax checker, aws-integration, validation

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