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YAML Validator & Formatter

Validate YAML syntax and convert between YAML and JSON. All processing happens in your browser.

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YAML Validator & Formatter

Validate YAML syntax and convert between YAML and JSON. All processing happens in your browser.

InputYAML
OutputYAML
Supports multi-document YAML separated by ---
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How to Use YAML Validator & Formatter

  1. 1

    Paste your YAML or JSON

    Paste YAML to validate or convert to JSON, or paste JSON to convert to YAML.

  2. 2

    Choose an action

    Use Validate to check syntax, YAML to JSON to convert, or JSON to YAML to go the other direction.

  3. 3

    Review the output

    See the converted or validated result in the output panel. Errors show line numbers.

  4. 4

    Copy the result

    Click Copy to copy the output to your clipboard.

Frequently Asked Questions

No. All validation and conversion happens entirely in your browser. Your data never leaves your machine.

Yes. You can use --- separators between multiple YAML documents and they will be parsed individually.

The validator detects syntax errors like invalid indentation, duplicate keys, and malformed values, with line numbers when available.

Yes. Switch to the JSON to YAML tab, paste your JSON, and click Convert to get formatted YAML output.