JSON Formatter

How to format JSON

1. Paste or load it: paste JSON into Input JSON, choose Upload for a .json or .txt file, or choose URL to have your browser request JSON from a URL.
2. Choose the operation: Beautify adds line breaks and indentation. Minify serializes the parsed value without formatting whitespace.
3. Choose indentation: open Indent: 2 and choose 2 Spaces, 4 Spaces, 8 Spaces, or Tab. The setting affects Beautify output; Minify remains one compact line.
4. Inspect and save: use Editor, Tree, Table, or Types on the output side, then use its Copy or Download icon.

Examples

Minified API response to readable JSON

Paste this 103-byte response and choose Beautify with two spaces:

{"user":{"id":42,"active":true},"items":[{"sku":"A-17","qty":2},{"sku":"B-04","qty":1}],"note":"ready"}

{
  "user": {
    "id": 42,
    "active": true
  },
  "items": [
    {
      "sku": "A-17",
      "qty": 2
    },
    {
      "sku": "B-04",
      "qty": 1
    }
  ],
  "note": "ready"
}

Trailing commas and single quotes

{'name':'Ada', 'items':[1,2,],} is not strict JSON, but this formatter's repair fallback removes the trailing commas and changes single quotes before parsing. It therefore shows the repaired object and does not show an error message or line/column for this input. For portable JSON, write "name":"Ada", use double-quoted keys and strings, and remove the trailing commas.

For a syntax error the repair fallback cannot fix, the tool displays the parser message. With {"name":"Ada" "role":"admin"}, the tested output begins: Invalid JSON: Expected ',' or '}' after property value in JSON at position 15 (line 2 column 2). Add the missing comma after "Ada".

Minify before and after

The formatted example above is 186 UTF-8 bytes. The formatter's Minify output is 103 bytes, saving 83 bytes (44.6%). The count is for this exact sample, not a promised saving for every JSON document.

Common JSON errors and how to fix them

Format JSON in code

These snippets use the standard formatting APIs and were checked for valid syntax:

// JavaScript
JSON.stringify(obj, null, 2)

# Python
json.dumps(obj, indent=2)
python -m json.tool input.json

# jq
jq . input.json

// Go
json.MarshalIndent(value, "", "  ")

For a strict syntax check before formatting, use the JSON Validator. After formatting, the JSON Editor Tree View is better suited to editing values.

What the formatter changes and what it doesn't

Beautify changes whitespace between JSON tokens. Minify removes that presentation whitespace. In tested runs, object key order stayed in its input order, duplicate keys collapsed to the last value, and 9007199254740993 became 9007199254740992 because the browser parses numbers as JavaScript numbers. An escaped \u00e9 was emitted as é, while two spaces and a newline escape inside a string remained part of the string. Do not use this tool as a lossless transport for integers beyond JavaScript's exact-number range.

Formatting does not turn JSON into YAML or edit values intentionally. For conversions, use JSON to CSV or JSON to XML; to inspect a changed payload, use the Diff Checker.

Privacy

Parsing, repair, formatting, and minifying happen in your browser in this page's JavaScript. Your pasted JSON is never sent to our servers by the formatter. If you use the URL option, your browser requests that URL directly and the response is then placed into the tool; that request is separate from sending data to T00LZ. Files are read with the browser's FileReader and are not uploaded by this tool.

Limits

There is no application-defined byte limit in the formatter code: uploads are read with FileReader, and pasted text is held in React state. Processing time and memory depend on the browser, device, and document shape. The page does not promise a maximum file size, so test larger files with care.

FAQ