JSON Formatter

Beautify, validate and fix JSON online — handles trailing commas and AI code fences. 100% private, runs in your browser. Free, no signup.

Examples

Indentation

JSON input

Paste JSON or choose an example to begin.

Everything stays in this browser.

Result

Formatted JSON

{
  "name": "Alex",
  "active": true,
  "roles": [
    "developer",
    "admin"
  ]
}

Search keys or values

JSON Example

This example is an object with one user. Keys name pieces of data, while values can be strings, numbers, booleans, arrays or nested objects. Load it to see the same data in the formatter, tree view and X-Ray summary.

{
  "user": {
    "id": 1042,
    "name": "Alex",
    "active": true,
    "roles": ["developer", "admin"],
    "profile": {
      "country": "US",
      "timezone": "America/New_York"
    }
  }
}

How to format JSON

Paste JSON or load an example
Put a JSON document in the input, or load one of the built-in examples to see the workflow without sending data anywhere.
Choose Format or Minify
Format adds readable indentation; Minify removes unnecessary whitespace when you need a compact JSON string.
Validate and review the issue
Use Validate to check JSON syntax. If the input is a common copy-and-paste mistake, use Repair and review the resulting JSON before reusing it.
Inspect or copy the result
Switch between Code, Tree and X-Ray to inspect the output, then copy the formatted JSON or a JSON path you need.

When a JSON formatter is useful

An API response is hard to read

A developer or support teammate can format a compact response before checking nested fields, status values or an unexpected property.

A configuration file will not parse

Before saving a JSON configuration, validate it to find syntax errors such as a trailing comma or an unquoted key.

A pasted payload needs a safe review

Use the local tree and X-Ray views to inspect a copied payload, including its structure and large-number warning, before sharing a result.

What Is JSON?

JSON is a lightweight, text-based format for structured data. People and programs use it to exchange information because it is readable, broadly supported and independent of a particular database or programming language. APIs often return JSON; apps also use it for settings, exports and configuration.

What Is JSON Data?

A JSON document contains one root value. In practice that root is usually an object or array. Objects group named fields; arrays keep an ordered list. Each field or item uses one of the JSON value types below.

ObjectNamed properties between { }

ArrayOrdered items between [ ]

StringText in double quotes

NumberA finite numeric value

Booleantrue or false

NullThe literal null value

What Is the JSON Format?

JSON has a small set of strict rules. Small punctuation mistakes can make an API response or configuration file invalid, so a formatter is useful before you share or save a document.

Use double quotes for every key and string.
Wrap objects with { } and arrays with [ ].
Separate object properties and array items with commas.
Do not leave a comma after the final item.
Put one colon between an object key and its value.
Use true, false and null in lowercase.
Numbers cannot include leading plus signs or NaN.
Escape a quote inside a string with a backslash.
Do not add comments; standard JSON has no comment syntax.
Keep every opening brace and bracket matched with a closing one.

Common broken input

{
  name: 'Alex',
  active: True,
}

After common repair

{
  "name": "Alex",
  "active": true
}

Valid JSON

What Is JSON Schema?

JSON Schema is a separate standard for describing expected JSON structure: required fields, permitted value types, formats and more. JSON is the data; a schema is a contract for that data. This tool currently validates JSON syntax and helps inspect its shape. It does not claim to validate a JSON Schema.

Common JSON Errors

The repair action handles a limited, predictable set of copy-and-paste mistakes: comments, simple unquoted keys, single-quoted strings, Python-style True/False/None and trailing commas. Review repaired output before using it in production.

FAQ

JSON Formatter FAQ

How do I format JSON online without uploading it?

Paste your JSON into the formatter and choose Format. Everything runs in your browser, so the text is not uploaded to ToolkitLoop.

Can it fix JSON with trailing commas?

Yes. The repair option can remove common trailing commas and shows the result for you to review before using it.

Can I clean up JSON copied from ChatGPT / AI tools?

Yes. Paste the response as-is. The formatter can handle common AI code fences and highlights syntax issues that still need attention.

What's the difference between JSON Formatter and JSON Validator?

The formatter makes valid JSON readable and can repair a few common mistakes. The validator focuses on finding and explaining syntax errors.

Related tools

Formatted JSON

JSON Example

How to format JSON

Paste JSON or load an example

Choose Format or Minify

Validate and review the issue

Inspect or copy the result