What does the validator check?

It parses the input with js-yaml's load function. Non-empty input that parses successfully is marked Valid YAML, invalid input is reported with js-yaml's parser message and, when available, the marked one-based line number; empty or whitespace-only input is handled as Empty input.

Does it also show me the parsed values?

Yes. A successful parse renders the resolved mapping, sequence, and scalar types as pretty-printed two-space JSON, so you can see whether yes stayed a string, null resolved to null, and whether nesting came out as expected.

Does it accept multi-document YAML?

No. It parses one YAML document at a time. For multi-document streams, split on the --- document markers and validate each one separately.

No. Parsing happens entirely in your browser; the input is never sent to a server, logged, or stored.

YAML Validator

Validate YAML syntax and preview the parsed JSON — all in your browser

YAML Input

Paste or type YAML to validate

Result

Validation status & JSON

Valid YAML

{
  "name": "devtools",
  "version": 1,
  "features": [
    "yaml",
    "json"
  ],
  "nested": {
    "enabled": true,
    "count": 3
  }
}

YAML Validator

YAML Input

Result

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YAML Input

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Related guides

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