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GitHub Actions Validator & Linter Online — Free GHA YAML Workflow Checker

GitHub Actions Validator

Validate, format and summarize GitHub Actions workflow YAML files against official schemas.

Ensure your CI/CD pipelines are error-free with official GitHub Actions schema validation. This tool checks your YAML for syntax errors, missing required fields, and semantic issues like invalid 'uses' paths, cyclic dependencies, or hardcoded secrets. It supports GitHub Workflows, Composite Actions, and Reusable Workflows. Features include real-time client-side validation, YAML/JSON formatting, and high-level workflow summaries to help you understand complex pipelines at a glance.

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Tags: github, actions, yaml, ci-cd, validate, workflow

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GitHub Actions Validator is also known as: GitHub Actions Linter, GHA YAML Checker, Workflow Validator Online, GitHub Workflow Syntax Checker.

How to GitHub Actions Validator Online

  1. Paste your GitHub Actions workflow YAML or action.yml content into the input area. The tool automatically detects if it's a Workflow or an Action.

  2. Choose your preferred indentation size (2, 4, or 8 spaces) and select an output format (YAML or JSON) from the bottom options panel.

  3. Click the Validate button or press ⌘⇧V (Mac) / Ctrl+Shift+V (Windows) to instantly check for structural errors against the official GitHub Actions JSON Schema.

  4. Review the Issues Found section to see specific errors, warnings, and their exact line numbers in your workflow file.

  5. Click Format to clean up indentation and normalize your YAML, or use the Summary action to get a high-level overview of jobs, triggers, and steps.

GitHub Actions Validator Features

  • Official Schema Validation: Validates your YAML against the latest official GitHub Actions JSON schemas for workflows and actions.

  • Semantic Checks: Performs deep logic checks beyond basic syntax, including valid 'uses' formats, existing 'needs' references, and deprecated commands.

  • Workflow Type Detection: Intelligent heuristic automatically identifies if you are editing a standard Workflow, a Composite Action, or a Reusable Workflow.

  • Line-Level Error Reporting: Maps schema validation errors back to exact line and column numbers in your YAML for effortless debugging.

  • YAML to JSON Conversion: Instantly convert complex GitHub Actions YAML into JSON format for programmatic analysis or storage.

  • Deprecated Command Alerts: Automatically identifies and flags deprecated workflow commands like ::set-output, suggesting modern alternatives like $GITHUB_OUTPUT.

  • Security Best Practices: Includes built-in checks for permissions and security hardening to help you build safer CI/CD pipelines.

  • Compressed URL Sharing: Share your entire workflow with teammates via gzip-compressed URL parameters that respect privacy.

  • Privacy-First Execution: All validation and formatting occurs entirely in your browser. Your sensitive workflow logic and secrets never touch our servers.

  • Developer Shortcuts: Native support for ⌘⇧V (Validate), ⌘⇧F (Format), and ⌘⇧S (Summary) for a high-velocity development experience.

Frequently Asked Questions

What is a GitHub Actions Validator?
A GitHub Actions Validator is a tool that checks your workflow YAML files for syntax errors and structural issues. It ensures that your triggers, jobs, and steps follow the official GitHub Actions specification, preventing failed runs and deployment delays.
Does it support action.yml for custom actions?
Yes. The tool automatically detects if you have pasted a Workflow file (with 'on' and 'jobs') or an Action metadata file (with 'name', 'description', and 'runs') and applies the appropriate official schema.
Can I use this to fix indentation in my YAML?
Absolutely. Use the 'Format' action to instantly normalize your YAML indentation to your preferred size (2, 4, or 8 spaces). It removes extra whitespace while preserving the semantic structure of your workflow.
What are semantic checks?
Beyond checking if the YAML is valid, semantic checks look at the logic. For example, our tool verifies that a job listed in 'needs' actually exists in the workflow, and that 'uses' strings follow the required 'owner/repo@ref' format.
Why should I avoid ::set-output?
GitHub has officially deprecated the '::set-output' command for security reasons. Our validator flags these instances and recommends using the modern environment file approach: 'echo "name=value" >> $GITHUB_OUTPUT'.
Is my workflow data safe?
Yes. This tool is built with a privacy-first architecture. All parsing, validation, and formatting logic runs locally in your web browser. No workflow data is ever sent to our backend or stored on our servers.
Does it support reusable workflows?
Yes. The validator recognizes the 'workflow_call' trigger and validates the inputs, outputs, and secrets specific to reusable workflow patterns.

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