YAML Validator
Check YAML for syntax errors, including the tab characters YAML forbids.
Your result will appear here as soon as you add some input.
How to use it
- 1Paste your document into the input box, or type it directly.
- 2Adjust the options if you need something other than the defaults.
- 3The result updates as you type.
- 4Copy the result to your clipboard or download it as a file.
About the YAML Validator
Three problems account for most invalid YAML: inconsistent indentation, a tab character used for indentation, and an unquoted value containing a colon followed by a space. All three are reported specifically.
Parsing uses the JSON-compatible schema, which refuses custom type tags. A document that relies on language-specific tags to construct objects is rejected here - and that is the same construct behind several remote code execution vulnerabilities in YAML loaders.
Questions people ask
Why does my value "no" become false?
Older YAML versions treat no, yes, on and off as booleans. Quote the value - "no" - if you mean the word. Country code NO in an unquoted list is the classic case.
Is your document uploaded to a server?
No. This tool runs entirely in your browser using standard web APIs, so your document never leaves your device. You can confirm it by opening your browser's network panel while the tool runs, or by disconnecting from the internet after the page has loaded.
Is it free, and do I need an account?
Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.