GitHub Actions Validator | Workflow YAML Linter

GitHub Actions validator that checks workflow YAML for schema errors, retired runners, outdated actions and script injection before you push. Free.

Also known as: github actions validator · github workflow validator · validate github actions yaml online · github actions linter · github actions syntax checker · github workflow yaml validator · github actions security checker · github actions checker online

devops and infrastructure tools

git and version control tools

xml and yaml tools

validators

Workflow YAML Input

Validation Results

Errors, warnings and suggestions for your workflow will appear here

About GitHub Actions Validator

A GitHub Actions validator checks a workflow file before you push it, so a typo or a retired runner does not cost you a failed run. Paste a .github/workflows YAML file and get each problem with its line number: schema errors, broken needs: references, runner images GitHub has retired, outdated action versions, and the script injection and pull_request_target mistakes attackers look for.

Key Features

Validates every top-level, job and step key, trigger event and permission scope against the current GitHub workflow schema, with did-you-mean suggestions for typos
Checks cron schedules field by field, flags intervals under GitHub's 5-minute floor and validates schedule time zones such as America/New_York
Finds needs: entries that point at missing jobs and dependency cycles that would stop every job in the chain from starting
Flags retired runner labels like ubuntu-20.04 and windows-2019, artifact actions at v3 that fail since January 2025, and actions still on Node 16
Catches script injection from issue titles, pull request bodies and branch names, unpinned third-party actions, write-all tokens and checkouts of fork code under pull_request_target

Use Cases

Check a new deploy workflow for an AWS us-east-1 release pipeline before opening the pull request
Audit every workflow in a repo for script injection and over-broad GITHUB_TOKEN permissions ahead of a SOC 2 review
Find out why a job sits in Queued forever after GitHub retired the runner image it asks for
Upgrade a 2023-era workflow by listing every action still on Node 16 and the major version to move to
Debug a schedule that fires at the wrong hour by confirming the cron fields and the time zone it runs in

Supported Formats

.github/workflows/*.yml

.yaml

Reusable workflows

Composite job steps

Related Keywords

github actions validator

github workflow validator

validate github actions yaml online

github actions linter

github actions syntax checker

github workflow yaml validator

github actions security checker

github actions checker online

How do I validate a GitHub Actions workflow before pushing?

Paste the file here and fix anything marked as an error: GitHub rejects the whole workflow on an unknown key, a bad event name or a broken expression, and you only find out after the push. For repeat checks, run actionlint locally or in a pre-commit hook. Warnings cover what still runs but hurts later, such as a third-party action pinned to a moveable tag, the way tj-actions/changed-files was compromised in March 2025.

Your workflow stays in your browser

Validation runs entirely in your browser with no upload, so internal job names, runner labels and secret names never leave your machine.

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Frequently asked questions

What is GitHub Actions Validator used for?

GitHub Actions validator that checks workflow YAML for schema errors, retired runners, outdated actions and script injection before you push. Free.

Is GitHub Actions Validator free to use?

Yes. GitHub Actions Validator is completely free with no usage limits, and there is no paid tier required to use it.

Do I need an account to use GitHub Actions Validator?

No. GitHub Actions Validator works immediately in your browser with no signup, login, or email address required.

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