Does this support the full YAML spec?

No, it supports a common subset: nested mappings, lists, scalars, and inline flow arrays — not anchors or multi-line block scalars.

Is my YAML sent anywhere?

No, all parsing happens locally in your browser.

What happens if my YAML is invalid?

You'll see a clear error message pointing to the problematic line.

YAML Validator

Validate YAML and preview it as JSON.

Works Offline

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No Login

No API

This validator supports a common subset of YAML: nested mappings, lists, scalars, and inline flow arrays. It does not support anchors, multi-line block scalars, or full YAML 1.2 spec features.

YAML Input

Valid — JSON preview

{
  "name": "Ada",
  "age": 28,
  "roles": [
    "admin",
    "editor"
  ],
  "address": {
    "city": "London",
    "zip": "E1 6AN"
  }
}

About the YAML Validator

Paste YAML to validate its structure and see a live JSON preview of nested mappings, lists, and scalars, with clear error messages when the indentation or syntax is invalid.

Examples

Simple mapping

name: Ada
age: 28

Output

{"name":"Ada","age":28}

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-07 · Runs entirely in your browser