YAML Formatter & Validator
Format, validate and convert YAML online for free. Instant syntax errors with line numbers, plus YAML to JSON and JSON to YAML conversion. Browser-only.
Frequently asked questions
- Are my files uploaded to a server?
- No. This tool runs entirely in your browser using JavaScript — your files never leave your device.
- Does it validate YAML?
- Yes — invalid YAML shows the parser error with the line and column, so you can spot bad indentation or stray tabs immediately.
- Can I convert between YAML and JSON?
- Yes, both directions: paste YAML and click 'To JSON', or paste JSON and click 'To YAML'.