All tools/Formatting

YAML Formatter & Validator

Validate YAML and re-serialize it cleanly, or convert it to JSON. Runs entirely in your browser.

How this works & FAQ

Paste YAML and click Validate & Format to check it parses correctly and re-print it in normalized YAML, or Convert to JSON to see the equivalent JSON. Errors show the line where parsing failed.

Is my data uploaded anywhere?

No. Parsing happens locally in your browser using the js-yaml library, loaded once from a CDN — your YAML content itself is never sent anywhere.

Why does it say my YAML is invalid?

Common causes: inconsistent indentation (YAML is whitespace-sensitive), tabs instead of spaces, or missing colons after keys.