JSON Formatter API

Format, beautify, minify, and validate JSON online. Custom indentation, key sorting, and precise error locations. 100% client-side — your data never leaves your browser.

The JSON Formatter is also available as a free REST API. Send a POST request with a JSON body to https://dot.tools/api/tools/json-formatter — 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`	"beautify" \| "minify" \| "validate"	required	Beautify with indentation, minify to a single line, or validate only.
`input`	string	required	The JSON text to format, minify, or validate.
`indent`	"2" \| "4" \| "tab"	required	Indentation used when beautifying: 2 spaces, 4 spaces, or tabs.
`sortKeys`	boolean	required	Sort object keys alphabetically (recursively) before output.

Response

Field	Type	Required	Description
`output`	string	required	The formatted JSON, or the original input in validate mode. Empty when invalid.
`valid`	boolean	required	Whether the input is valid JSON.
`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/json-formatter \
  -H 'Content-Type: application/json' \
  -d '{
  "mode": "beautify",
  "indent": "2",
  "sortKeys": false,
  "input": "{\"name\":\"dot.tools\",\"version\":\"2.0.0\",\"private\":true,\"tools\":[\"json-formatter\",\"xml-formatter\",\"yaml-json\"],\"meta\":{\"clientSide\":true,\"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 JSON Formatter in your browser, read the JSON Formatter guide, or import the full OpenAPI specification.