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Online JSON Formatter and Beautifier

Format JSON for free, no signup required. Pasted text and local files are processed in your browser.

Your data stays in this browser

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AuditableDocumented semantics

PortableCorrectly typed downloads

JSON Formatter: How to use this tool

Format, beautify and validate JSON online with 2, 3 or 4-space indentation. Preserve large numbers and keep your data in your browser.

Format JSON for free, no signup required. Pasted text and local files are processed in your browser.

Open guide and examples

How to use this tool

Paste JSON, upload a local file, or load a CORS-enabled public URL.
Optionally choose indentation in Advanced, then run Format JSON.
Review the result, then copy it or download it with the correct file type.

Example to try

Input JSON

{"project":"jsonformatters.org","status":"ready","features":["format","validate","convert"],"settings":{"indent":2,"sortKeys":false,"localOnly":true},"documents":[{"id":101,"name":"launch-config.json","valid":true},{"id":102,"name":"sample-data.json","valid":true}],"lastError":null}

Result

{
  "project": "jsonformatters.org",
  "status": "ready",
  "features": [
    "format",
    "validate",
    "convert"
  ],
  "settings": {
    "indent": 2,
    "sortKeys": false,
    "localOnly": true
  },
  "documents": [
    {
      "id": 101,
      "name": "launch-config.json",
      "valid": true
    },
    {
      "id": 102,
      "name": "sample-data.json",
      "valid": true
    }
  ],
  "lastError": null
}

JSON formatter guide

What JSON formatting changes and preserves

Formatting changes whitespace, not data; it does not sort keys or repair invalid JSON.

Valid JSON only

Input must be one JSON value. Comments, trailing commas, unquoted keys, single-quoted strings, NaN, Infinity, and undefined are invalid. Find errors with the JSON validator, or try documented fixes with the JSON repair tool. Repairs change the source.

Tokens stay intact

Numbers and strings—including large integers, exponents and escapes— keep their tokens. Member and array order, plus duplicate members, also remain; only whitespace outside strings changes. Duplicate names are non-portable under RFC 8259, so retain the source when exact bytes or ambiguity matter.

Choose the right tool

The JSON minifier gives compact, token-preserving output. The JSON viewer builds a tree but rejects duplicate names and inexact JavaScript numbers.

Primary sources: See RFC 8259 §2, RFC 8259 §4, RFC 8259 §6 · ECMA-404

Learn

Frequently asked questions

Does formatting or beautifying also validate JSON?

Both rewrite whitespace and confirm strict syntax, not JSON Schema or application rules.

Are large JSON numbers preserved?

Yes. Output keeps number tokens; later parsers may round values outside JavaScript's safe range.

Does this tool upload my JSON?

Pasted text and local files stay in your browser. URL import makes a request to the address you enter.

What happens to invalid JSON?

It reports a likely error location and no output. Review any changes made by JSON Repair.

Which indentation sizes are available?

Choose 2, 3, or 4 spaces in Advanced; tokens, duplicate members, and member and array order stay intact.

What limits does JSON Formatter apply?

Limits: 2 MB input, 8 MB output, 256 nesting levels, and 200,000 JSON nodes.

Practical JSON guides

JSON format vs validate vs minify: what each operation changes

Understand when to format, validate, or minify JSON, what each operation proves, and which representation changes you should review.

Common JSON syntax errors and how to fix them safely

Diagnose common JSON syntax errors, including quotes, commas, comments, escapes, numbers, and missing delimiters, without guessing at data meaning.