YAML Validator
Validate, format, and convert YAML files instantly. 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.
All validation happens in your browser. No data is sent to any server.
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How to Use
- 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 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 Format or convert — Use Format to beautify with consistent indentation, Minify to compress, or convert between YAML and JSON formats.
- 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 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.