YAML Validator

Validate YAML syntax and find errors instantly in your browser

Paste YAML on the left to validate...

What is YAML Validator?

The YAML Validator checks your YAML syntax for errors and reports them with exact line numbers, making it easy to find and fix problems in configuration files. YAML is used in Docker Compose, Kubernetes, GitHub Actions, Ansible, and many other tools — a single indentation mistake or tab character can break an entire deployment. This tool catches common YAML errors instantly in your browser without any server upload.

Why Use DevBench YAML Validator?

DevBench YAML Validator runs entirely in your browser — your data never leaves your device. No sign-up, no limits, no watermarks, completely free forever.

How to Use YAML Validator

  1. Paste your YAML content into the input textarea
  2. Errors appear instantly with line numbers
  3. Click Load Sample to see correct YAML syntax
  4. Fix the errors shown and re-paste to confirm the YAML is clean
  5. Use for validating config files before deployment

Examples

  • Validate a Docker Compose YAML file before running docker-compose up
  • Check a Kubernetes manifest for syntax errors before kubectl apply
  • Validate a GitHub Actions workflow YAML before pushing
  • Check an Ansible playbook YAML for indentation errors
  • Validate a config.yaml file for a web application

Use Cases

  • DevOps engineers validating Kubernetes and Docker YAML files
  • Developers checking GitHub Actions workflow syntax
  • Ansible users validating playbook YAML before running
  • Anyone debugging YAML indentation and syntax errors
  • CI/CD pipeline developers catching YAML errors early
  • Students learning YAML syntax rules
  • Teams reviewing configuration files before deployment

Frequently Asked Questions

What are the most common YAML errors?

The most common YAML errors are: using tab characters instead of spaces for indentation, inconsistent indentation levels, missing spaces after colons, and unmatched quotes.

Why does YAML not allow tabs?

The YAML specification explicitly forbids tab characters for indentation because different editors display tabs at different widths. Always use spaces — 2 spaces per level is the most common convention.

Is my YAML sent to a server?

No. All validation runs entirely in your browser using JavaScript. Your YAML content never leaves your device.

Does this validate YAML schemas?

This tool validates YAML syntax only. It does not validate against a specific schema like Kubernetes CRD schemas. For schema validation, use a dedicated schema validator.

What indentation should I use in YAML?

Use 2 spaces per indentation level. This is the most widely accepted YAML convention used by Kubernetes, Docker Compose, and GitHub Actions.