YAML validator
Does it parse — and does it mean what you think?
Output
Paste or type above to see the result here.
Your files stay on your device
This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
How it works
- Paste the YAML. It is checked as you type.
- If it does not parse, the line is named and the lines around it are shown.
- If it does parse, look at the warnings underneath.
- Fix and paste again.
Frequently asked questions
- Why warn about something that parses?
- Because the mistakes that actually cost time are the ones that parse. country: no is the boolean false, not Norway. version: 1.2.3 is text but 1.2 would be a number. code: 0755 loses its leading zero. Quoting any of them fixes it, and nothing tells you until something downstream misbehaves.
- Why is a tab an error rather than a warning?
- Because YAML forbids tabs for indentation outright — it is one of the few things the specification is blunt about. Editors that insert them silently are the usual cause.
- Which version of YAML is this?
- The parser handles the subset that configuration files actually use: mappings, lists, block and flow styles, multi-line strings, anchors in the common form. Exotic corners of the specification may not be covered, and it will say so rather than guessing.
- Can I convert it as well?
- Yes — our YAML to JSON and JSON to YAML pages do that, using this same parser.
- Is anything sent to a server?
- No. It runs in your browser, so what you paste stays on your computer.
Related tools
⇄ Converters YAML to JSON Paste YAML, get JSON. Nothing is uploaded, and nothing is guessed at. ⇄ Converters JSON to YAML Paste JSON, get YAML. It runs in this page, not on a server. {} JSON Formatter Paste JSON, get it indented, minified or validated instantly. Your data stays on this page. ≠ JSON diff What actually changed, as a path.