Overview
Paste YAML to get a direct valid/invalid verdict, using js-yaml’s safe load() - the same parser behind the YAML Formatter and YAML Parser - so nothing is ever executed, only parsed. This is a validation-only tool: it doesn’t reformat the source (that’s the YAML Formatter’s job) and it doesn’t render an expandable tree (that’s the YAML Parser’s job); it just answers the one question of whether the YAML is well-formed, with the parser’s exact error message when it isn’t, plus a minimal root-type and item-count summary when it is. Useful when you just need a fast pass/fail on a config file or CI-generated YAML without the extra output of a full formatter or structure viewer. Runs entirely client-side.
Best for: Getting a fast pass/fail on a config file without reformatting it
How to use this tool
- Paste your YAML. A config file, Kubernetes manifest, or any YAML document.
- Instant syntax check. js-yaml’s safe load() validates as you type and reports a pass/fail verdict immediately.
- Error message on failure. Invalid YAML shows the parser’s exact error message.
- Structure summary on success. Valid YAML gets a quick root-type and top-level item count.
Why use this tool
Validation-only, nothing else
No reformatted output or tree view to work through - just a direct verdict.
Safe parsing only
Uses js-yaml’s load(), which never instantiates arbitrary JS types from YAML tags.
Nothing leaves your browser
Parsing happens entirely client-side.
Frequently asked questions
All three share the same safe js-yaml parser, but they’re built for different moments. The Formatter reformats YAML source into cleanly indented YAML. The Parser renders the parsed value as a real, expandable JSON-equivalent tree. This Validator skips both and just gives a fast valid/invalid verdict with the parser’s error message, for when that’s the only thing you need.
No - it’s only parsed, via js-yaml’s load(), the safe loader in js-yaml 4.x. It never evaluates code or instantiates arbitrary classes from custom YAML tags.