YAML Formatter & Validator — Pretty-Print YAML, Free

Format, validate, and pretty-print YAML files instantly. Convert between YAML and JSON. 100% free, processed in your browser.

Data never uploadedSyntax validationYAML ↔ JSON convert

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How to Format YAML

Paste your YAML string into the editor or upload a .yaml / .yml file.

Click Format to pretty-print, or Convert to JSON to transform the data. Errors are shown instantly.

Copy the formatted result to clipboard or download as a .yaml or .json file.

Is the YAML Formatter free?

Yes, 100% free with no account required.

Does it validate YAML?

Yes. Syntax errors are detected and reported with line numbers and descriptions.

Can I convert YAML to JSON?

Yes. Click the Convert to JSON button to transform your YAML into JSON format.

Is my data safe?

All processing happens in your browser. No data is sent to any server.

What YAML versions are supported?

YAML 1.1 and 1.2 are both supported via the js-yaml library.