JSON Formatter & Validator

What does this tool do?

JSON is a text format for exchanging objects, arrays and values. Valid syntax lets applications parse it. This tool formats JSON with two spaces and checks its syntax; use it to inspect API responses, configuration files or test data. Processing happens in your browser.

How to use it

1. Paste JSON into the editor or select Example.
2. Select Format JSON to validate syntax and organize the data.
3. If an error appears, check quotes, commas and delimiters; correct the input and try again.
4. Review the output and select Copy result to use it in your project.

Input and output examples

{"order_id":42,"total":19.95,"customer":{"name":"Ada"},"tags":["paid"],"note":null}

{
  "order_id": 42,
  "total": 19.95,
  "customer": {
    "name": "Ada"
  },
  "tags": [
    "paid"
  ],
  "note": null
}

Important limitations

• Checks syntax, not a JSON schema or business rules: a missing required property can still pass validation.
• Does not repair errors or support comments, trailing commas or JSON5 syntax.
• Uses JavaScript numbers: integers outside the safe range can lose precision. Duplicate keys retain only the last value; formatting does not preserve the original number or whitespace representation.
• Very large or deeply nested data can consume memory or temporarily block the tab.

Common mistakes

• Using single quotes or property names without double quotes.
• Leaving a comma after the last object property or array element.
• Missing a brace, bracket or colon between a property and its value.
• Pasting a JavaScript object with undefined, NaN or comments instead of valid JSON.

Frequently asked questions