Which YAML features are supported?

This tool uses js-yaml, which supports the full YAML 1.1/1.2-style spec including anchors (&) and aliases (*), block and flow styles, multi-line strings, and standard scalar types (numbers, booleans, null, dates). It does not merge multiple '---' documents in a single file — only the first document in a multi-document YAML file is parsed.

If I convert JSON to YAML, will comments be preserved?

No. JSON has no concept of comments, so there's nothing to carry over — the YAML output will be clean, comment-free data. If you need to convert YAML with comments to JSON, the comments are simply dropped in the output since JSON can't represent them either.

What indentation does the YAML output use?

JSON → YAML output uses 2-space indentation with block style by default, and long lines are not wrapped, so nested arrays and objects stay readable without arbitrary line breaks.

Is there a size limit on how large a file I can convert?

There's no hard-coded limit — conversion happens in your browser's memory, so very large files (tens of megabytes) may feel slow or use a lot of RAM depending on your device, but typical config files and data exports convert instantly.

Is my YAML or JSON data uploaded anywhere?

No. All parsing and conversion happens locally in your browser using JavaScript — nothing you type or paste is sent to a server.

YAML ⇄ JSON CONVERTER

Convert YAML to JSON or JSON to YAML with live output and clear parse errors. Nothing leaves your browser.

YAML

JSON

{
  "name": "Dimas' Toolbox",
  "version": 1,
  "tags": [
    "free",
    "client-side"
  ],
  "nested": {
    "key": "value"
  }
}

How to use the YAML ⇄ JSON converter

1
Choose YAML → JSON or JSON → YAML.
2
Type or paste your input into the left box.
3
Copy the converted result from the right box — it updates live as you type.

Questions

Which YAML features are supported?: This tool uses js-yaml, which supports the full YAML 1.1/1.2-style spec including anchors (&) and aliases (*), block and flow styles, multi-line strings, and standard scalar types (numbers, booleans, null, dates). It does not merge multiple '---' documents in a single file — only the first document in a multi-document YAML file is parsed.
If I convert JSON to YAML, will comments be preserved?: No. JSON has no concept of comments, so there's nothing to carry over — the YAML output will be clean, comment-free data. If you need to convert YAML with comments to JSON, the comments are simply dropped in the output since JSON can't represent them either.
What indentation does the YAML output use?: JSON → YAML output uses 2-space indentation with block style by default, and long lines are not wrapped, so nested arrays and objects stay readable without arbitrary line breaks.
Is there a size limit on how large a file I can convert?: There's no hard-coded limit — conversion happens in your browser's memory, so very large files (tens of megabytes) may feel slow or use a lot of RAM depending on your device, but typical config files and data exports convert instantly.
Is my YAML or JSON data uploaded anywhere?: No. All parsing and conversion happens locally in your browser using JavaScript — nothing you type or paste is sent to a server.