YAML Validator
Validate YAML syntax and check for errors.
Validation Checks:
- Consistent indentation (multiples of 2)
- Proper key-value pair format
- Valid list item syntax
- Matching quotes and brackets
- Proper nesting hierarchy
About YAML Validator
YAML Validator parses your YAML and reports any syntax errors with the line number and a clear description of what is wrong. YAML is notoriously whitespace-sensitive, so this tool is invaluable for catching indentation problems, tab characters (which are illegal in YAML), and other subtle mistakes before they cause runtime errors. It supports YAML 1.1 and 1.2.
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Frequently Asked Questions
Is YAML Validator free?
Yes, completely free. No signup, no account, no usage limits. Use it as much as you need.
Is my data secure?
All processing happens directly in your browser using JavaScript. Your data is never sent to any server, stored, or shared. It stays entirely on your device.
Why does YAML fail when I use tabs for indentation?
The YAML specification explicitly forbids tab characters for indentation. Use spaces only — 2 spaces per level is the most common convention.
Can I validate multiple YAML documents in a single file (separated by ---)?
Yes. YAML supports multi-document files using the --- separator and the validator will check each document independently.