About YAML Validator

Validates YAML syntax with the spec-compliant js-yaml parser and reports the first parse error it finds. Paste YAML directly or upload a .yaml/.yml file. Content can be copied to the clipboard or downloaded. Catches real YAML violations like bad indentation, duplicate keys, and malformed structures.

• Full-parser validation: runs the content through js-yaml, the same parser used in production tooling
• Reports the parser error message, which includes the line and column of the problem
• Handles nested mappings, sequences, comments, and multi-line scalars per the YAML spec
• File upload accepts .yaml and .yml files via a hidden file input
• Copy and download buttons for the YAML content

Frequently Asked Questions

Does this use a full YAML parser?

Yes. It runs your content through js-yaml, a spec-compliant parser, so it catches real violations such as incorrect indentation nesting, duplicate keys, and malformed structures—not just surface-level formatting.

Can it convert YAML to JSON?

No. This tool validates that your YAML parses successfully; it does not output or convert the parsed result to another format. It is a syntax check, not a format converter.