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JSON Formatter & Validator

Format, validate and minify JSON with 2-space, 4-space or tab indents, alphabetical key sorting and line-numbered parse errors.

JSON Formatter & Validator

Indent:
317 chars / 1 lines
Formatted output455 chars / 28 lines

Valid JSON, formatted

{
  "name": "Acme Toolkit",
  "version": "1.0.0",
  "features": [
    "JSON Formatter",
    "Base64 Tool",
    "URL Encoder",
    "UUID Generator",
    "Timestamp Converter"
  ],
  "config": {
    "theme": "dark",
    "indent": 2,
    "sortKeys": false
  },
  "metadata": {
    "created": "2026-02-11T00:00:00Z",
    "tags": [
      "developer-tools",
      "react",
      "astro"
    ],
    "stats": {
      "users": 1420,
      "rating": 4.8
    }
  }
}

Updated . Provided as is. Check the output before you rely on it in production.

How to use JSON Formatter & Validator

  1. 1

    Paste your JSON

    Paste JSON into the input panel or load the sample. Invalid JSON shows the parser's error message instead of output.

  2. 2

    Choose indentation or compact output

    Pick the indent width for pretty-printed output, or switch on Compact for single-line JSON.

  3. 3

    Sort keys

    Turn on Sort keys to order object keys alphabetically, which makes two JSON documents much easier to diff.

  4. 4

    Copy or download

    Copy the formatted output, or download it as a .json file to use in your project.

Questions and answers

What is JSON Formatter & Validator?
JSON is the text format most APIs and config files use for structured data. This tool validates it, pretty-prints it with 2-space, 4-space or tab indents, minifies it to one line, sorts keys alphabetically, and reports parse errors with the line number.
Can it handle large JSON files?
Yes. Formatting runs locally in your browser, so the size limit is your device's memory. Invalid input reports the parser's error so you can find the problem.
For AI agents: how to call this tool

Machine-readable contract, endpoints and examples. Humans can ignore this section.

Best Path For Builders

Browser workflow

Runs instantly in the browser with private local processing and copy/export-ready output.

Browser Workflow

This tool is optimized for instant in-browser execution with local data handling. Run it here and copy/export the output directly.

/json-formatter/

For automation planning, fetch the canonical contract at /api/tool/json-formatter.json.