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JSON formatter and validator

Paste a JSON document to check its syntax and format it with two-space indentation. Inspect nested objects and arrays, then copy the formatted result into an editor, a bug report, or your API notes.

Make your JSON readableProcessed in your browser
No account requiredRuns in your browserFree to use
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How to use this tool

  1. Paste JSON into the input field or use the prefilled example.
  2. Select Format JSON. Invalid input displays a syntax error instead of a formatted result.
  3. Review the output and select Copy to copy the formatted JSON.

Example input and output

Format an object with an array

Input

{"name":"Ada","tags":["tools","code"]}

Result

{
  "name": "Ada",
  "tags": [
    "tools",
    "code"
  ]
}

When to use it

Inspect an API response

Expand a compact response into readable lines so you can follow object nesting and array contents.

Check a configuration file

Catch JSON syntax problems such as missing quotes or trailing commas before using a configuration. This is a syntax check, not schema validation.

What to know before you use it

The formatter uses JavaScript JSON.parse and JSON.stringify. Large integers may lose precision; use strings for exact identifiers. Duplicate object keys are not preserved. Comments, trailing commas, JSON5, and JSON Schema validation are not supported.

Frequently asked questions

Does the formatter upload my JSON?

No. Parsing and formatting run in your browser. The tool does not send the input to a processing server.

Why is my JSON invalid?

JSON requires double-quoted property names and strings, and does not allow comments or trailing commas. Review the displayed parser message and check the surrounding syntax.

Does this validate a JSON Schema?

No. It checks JSON syntax only. A syntactically valid document can still fail your API or application schema.

Will it preserve very large numbers?

Not always. JavaScript numbers cannot represent all large integers exactly. Keep exact IDs and other precision-sensitive values as quoted strings, and retain your original input.

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