JSON Formatter, Validator & Beautifier Online

Free Online JSON Formatter and Validator

This JSON formatter (also known as a JSON beautifier, JSON pretty print, or JSON indent tool) takes minified, messy or unreadable JSON and reformats it into a clean, properly indented structure that is easy to read, scan and debug. It also works as a JSON validator — paste your data, click Validate, and the tool will tell you instantly whether the syntax is correct, pointing to the exact line and column of any error.

Everything happens in your browser. Your JSON is never uploaded, logged or stored anywhere, which makes this free online JSON formatter safe to use with API responses, configuration files, MongoDB documents, Swagger specs and any data you would not want sent to a third-party server.

How to Use the JSON Formatter

1. Paste your JSON into the input pane on the left.
2. Click Format to beautify, Minify to compress, or Validate to check syntax.
3. Choose your indent size — 2 spaces, 4 spaces, or Tab.
4. Click Copy to copy the result, or Download to save as a .json file.

You can also use Ctrl+Enter (or Cmd+Enter on Mac) as a keyboard shortcut to format instantly.

JSON Formatter Examples

Here are common before/after examples showing what the JSON beautifier does:

Example 1: Minified API Response

Input (minified):

{"users":[{"id":1,"name":"Ada","active":true},{"id":2,"name":"Linus","active":false}],"total":2}

Output (formatted with 2-space indent):

{
  "users": [
    {
      "id": 1,
      "name": "Ada",
      "active": true
    },
    {
      "id": 2,
      "name": "Linus",
      "active": false
    }
  ],
  "total": 2
}

Example 2: Configuration File

Input:

{"app":{"name":"myapp","version":"1.0.0","features":{"auth":true,"analytics":false}}}

Output (4-space indent):

{
    "app": {
        "name": "myapp",
        "version": "1.0.0",
        "features": {
            "auth": true,
            "analytics": false
        }
    }
}

JSON Beautify vs. JSON Minify

Beautifying (the same thing as formatting or pretty printing) adds indentation and line breaks so a human can read the JSON easily. Minifying does the opposite — it strips every unnecessary character to make the file as small as possible, which is what you want when sending JSON over the network or embedding it inside an HTML page.

For development and debugging, always use the formatter. For production payloads, minify to reduce bytes transferred.

Validate JSON Online

The built-in JSON validator uses your browser's native JSON parser to check syntax. When the JSON is invalid, the tool reports the exact line and column number of the first error so you can fix it quickly.

Most JSON syntax errors come down to a handful of common mistakes:

• Trailing commas — JSON does not allow a comma after the last item in an object or array.
• Single quotes — JSON requires double quotes around strings and keys; single quotes are invalid.
• Unquoted keys — keys must always be strings inside double quotes.
• Unescaped characters — characters like " and \ inside strings must be escaped as \" and \\.
• Mismatched brackets — every { needs a matching }, every [ needs a matching ].
• Comments — JSON does not support comments (use JSON5 or JSONC if you need them).

JSON Indent: 2 Spaces, 4 Spaces, or Tab

The JSON indent setting controls how nested content is indented. Different teams have different conventions:

• 2 spaces — the most common modern convention, used by Prettier, ESLint default, and most Node.js projects.
• 4 spaces — common in Java, Python and older codebases.
• Tab — preferred by some editors and accessibility-focused codebases because each developer can configure tab width.

Use the dropdown next to the Format button to pick your preferred indent.

Working With Different JSON Sources

This formatter handles JSON from any source:

• API responses — paste raw JSON from REST APIs, GraphQL responses, or webhooks.
• JSON files — open your .json file, paste its contents, and format it. This works as a JSON file formatter.
• Swagger / OpenAPI — paste your Swagger spec to format and validate it before publishing.
• MongoDB documents — paste BSON-flavored JSON from MongoDB; the validator will flag any non-standard syntax.
• Browser localStorage / sessionStorage — paste stringified JSON from your devtools.
• Configuration files — package.json, tsconfig.json, composer.json, etc.

Convert JSON to Other Formats

After formatting your JSON, you may want to convert it to another format. Use these companion tools:

• JSON to XML formatter — convert JSON into XML
• JSON to YAML — convert JSON to YAML
• JSON to CSV — flatten JSON arrays into CSV
• XML to JSON — go the other way
• YAML to JSON — convert YAML back to JSON
• CSV to JSON — turn spreadsheets into JSON

If your JSON contains Base64-encoded fields (common for embedded images, signatures, or binary data), use our Base64 decoder to inspect them, or our JWT decoder for JWT tokens.

Privacy & Security

This tool runs entirely client-side. There is no backend, no server-side processing, and no logging of the JSON you paste. You can verify this by opening your browser's developer tools (Network tab) and confirming that no requests are made when you click Format, Minify or Validate.

This makes the tool safe for sensitive data such as authentication tokens, customer records, and configuration files containing secrets.

Browser Compatibility

The JSON formatter works in all modern browsers — Google Chrome, Mozilla Firefox, Safari, Microsoft Edge, Opera, and Brave — on Windows, macOS, Linux, ChromeOS, iOS, and Android. No installation, no extension, no signup required.