Free Online YAML Validator
The YAML Validator checks your YAML for the errors that break most files: inconsistent indentation, tabs, duplicate keys, and malformed key/value lines. It reports the line number of each problem.
How to Use
Paste your YAML and click Validate. Any problems are listed with their line numbers; if it is clean you get a summary of the structure.
- Detects tabs used for indentation
- Flags inconsistent indentation between siblings
- Finds duplicate keys and malformed lines
- Reports the line number of each issue
- Runs entirely in your browser
Common YAML mistakes
YAML forbids tabs for indentation, requires consistent spacing for sibling keys, and treats a space after the colon as significant. This validator catches those cases before they reach your CI pipeline.
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