YAML ↔ JSON Converter API

Convert YAML to JSON and JSON to YAML online. Bidirectional, validated conversion with error locations. Free, fast, 100% client-side.

The YAML ↔ JSON Converter is also available as a free REST API. Send a POST request with a JSON body to https://dot.tools/api/tools/yaml-json — no authentication, no API key, CORS enabled. Successful calls return { "ok": true, "result": { … } }; failures return HTTP 400 or 422 with an error body.

Request body

Field	Type	Required	Description
`mode`	"yaml-to-json" \| "json-to-yaml"	required	Conversion direction: YAML to JSON, or JSON to YAML.
`input`	string	required	The YAML or JSON text to convert.
`indent`	"2" \| "4"	required	Number of spaces per indentation level in the output.

Response

Field	Type	Required	Description
`output`	string	required	The converted document. Empty when the input is invalid.
`valid`	boolean	required	Whether the input parsed successfully.
`error`	unknown	required	Parse error message when invalid.
`errorLine`	unknown	required	1-based line of the parse error when invalid.
`errorColumn`	unknown	required	1-based column of the parse error when invalid.

Example request

curl -X POST https://dot.tools/api/tools/yaml-json \
  -H 'Content-Type: application/json' \
  -d '{
  "mode": "yaml-to-json",
  "indent": "2",
  "input": "name: dot.tools\nversion: 2.0.0\nprivate: true\ntools:\n  - json-formatter\n  - xml-formatter\n  - yaml-json\nmeta:\n  clientSide: true\n  category: format"
}'

Sample response

{
  "ok": true,
  "result": {
    "output": "{\n  \"name\": \"dot.tools\",\n  \"version\": \"2.0.0\",\n  \"private\": true,\n  \"tools\": [\n    \"json-formatter\",\n    \"xml-formatter\",\n    \"yaml-json\"\n  ],\n  \"meta\": {\n    \"clientSide\": true,\n    \"category\": \"format\"\n  }\n}",
    "valid": true,
    "error": null,
    "errorLine": null,
    "errorColumn": null
  }
}

Use the free YAML ↔ JSON Converter in your browser, read the YAML ↔ JSON Converter guide, or import the full OpenAPI specification.