Code
Format and validate YAML locally with helpful parse errors.
Runs entirely in your browser
Nothing you paste is uploaded. Monaco and Prettier load on demand from this origin.
YAML
Formatted
Run the formatter to see output here.
There is no upload endpoint — your files are processed in this browser tab. Open your network tab and check. See how it stays private.
How to YAML formatter
- Paste YAML. Paste the YAML config you want to check.
- Format & validate. Indentation is normalized and errors are flagged.
- Copy. Copy the clean, valid YAML back to your file.
YAML's readability comes at the cost of fussy whitespace rules, and a single bad indent breaks a whole config. Formatting normalizes the structure and validation catches the error before your CI does.
To turn YAML into JSON or TOML, use the data converter; for other markup, see the XML formatter.
Frequently asked questions
Why is my YAML invalid?
YAML is whitespace-sensitive, so the usual culprits are inconsistent indentation, tabs instead of spaces, or mis-nested keys — the validator points to where parsing fails.
Can it convert YAML to JSON?
This tool focuses on formatting and validating; for conversions between JSON, YAML, and TOML use the dedicated data converter.
Is my YAML uploaded?
No. Parsing and formatting run in the browser, so your config stays on your machine.
Related tools
- JSON / YAML / TOMLConvert between JSON, YAML, and TOML data formats on your device.
- XML formatterPretty-print or minify XML in your browser with no upload.
- JSON toolkitFormat, validate, minify, and explore JSON in a collapsible tree — all in your browser.
- Compose validatorParse and validate docker-compose.yml syntax locally.