Skip to main content
Toolisti

YAML Validator

Validate, format, and convert YAML files instantly.

100% in-browser · no data sent

Check for syntax errors with helpful fix suggestions, convert between YAML and JSON, and explore document structure. Perfect for Docker Compose, Kubernetes, CI/CD configs, and more.

Embed This Tool

Add this tool to your website with customizable styling

Get Embed Code

How to Use

  1. 1
    Paste your YAML — Copy and paste your YAML content into the input area. Or use one of the quick sample buttons to load Docker Compose, Kubernetes, or GitHub Actions examples.
  2. 2
    Validate the syntax — Click Validate to check for errors. If issues are found, you'll see the line and column number along with common fix suggestions.
  3. 3
    Format or convert — Use Format to beautify with consistent indentation, Minify to compress, or convert between YAML and JSON formats.
  4. 4
    Explore the structure — For valid YAML, click Show Structure to see a tree view of your document with type information for each node.
  5. 5
    Copy or download — Copy the formatted YAML to your clipboard or download it as a .yaml file.

Frequently Asked Questions

What causes most YAML errors?

The most common YAML errors are: inconsistent indentation (mixing tabs and spaces, or wrong indent levels), missing colons after keys, unquoted special characters in values, and duplicate keys in the same block.

Should I use 2 or 4 spaces for indentation?

YAML requires consistent indentation but doesn't mandate a specific size. 2 spaces is standard in Docker, Kubernetes, and most YAML conventions. 4 spaces works too - just be consistent throughout your file.

Can I convert YAML to JSON and back?

Yes! Click 'YAML → JSON' to convert your YAML to JSON format. To convert JSON to YAML, paste JSON content and click 'JSON → YAML'. Note that YAML is a superset of JSON, so any valid JSON is also valid YAML.

What YAML formats are supported?

The validator supports all standard YAML 1.2 syntax including anchors and aliases, multi-line strings (literal and folded), complex keys, flow style (inline arrays/objects), and comments. It works with Docker Compose, Kubernetes manifests, Ansible playbooks, GitHub Actions, and any other YAML files.