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JSON Formatter

Format JSON online, validate its syntax, or minify it in your browser without uploading the data.

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JSON Formatter

Formatting runs in your browser. Sharing is optional and includes the JSON output in a readable link; never share secrets.

JSON output

Results and sharing

Choose two- or four-space indentation, format or minify, and switch to numbered output. Copy or download valid JSON. Share result includes the output in the link; never share secrets. Editing input clears old output.

Use Share result to preview and copy a link. Anyone with the link can read the included details; nothing is saved on our server. Shared result links open read-only snapshots. Large results require a downloaded file instead.

How to use it

  1. Paste strict JSON or choose JSON5 / Python-like syntax to normalize unquoted keys, single quotes, comments, and trailing commas.
  2. Choose Format or Minify; optionally sort keys and select code, numbered, or tree output.
  3. Inspect any parser error, then copy, download, or share the result. Shared links contain the output, so never include secrets.
What is JSON Formatter?

Validate, format, minify, copy, and download JSON with a quick browser-based parser.

How it works

Strict mode uses the browser's JSON parser. JSON-like mode normalizes unquoted keys, single-quoted strings, comments, and trailing commas, including Python-style True, False, and None. Output can be pretty-printed or minified, recursively sort object keys, and display as code, numbered lines, or a navigable tree.

Example input and expected output

Input

{"name":"SiteIndex","enabled":true}

Expected output

{
  "name": "SiteIndex",
  "enabled": true
}
Common uses
  • Make an API response easier to inspect during debugging.
  • Validate a JSON configuration file before using it.
  • Minify a valid JSON payload for a compact test fixture.
Limitations
  • Uses JavaScript JSON values after normalization: integers beyond the safe numeric range can lose precision, and duplicate property names retain the last value. Quote large identifiers to preserve them.
  • JSON-like mode supports common JSON5/Python-style object syntax, not executable expressions, functions, undefined, or NaN.
Frequently asked questions
Why is my JSON invalid?
Strict JSON requires double-quoted strings and property names and does not allow comments or trailing commas. Choose JSON5 / Python-like input syntax to normalize those common variants.
Does formatting change the data?
The tool parses and reserializes JSON, not just whitespace. Standard JSON values are retained, but JavaScript number precision applies, duplicate keys keep their last value, and integer-like object keys may be reordered. Quote large numeric identifiers before formatting.
Is the JSON sent to a server?
No. Parsing, formatting, and minifying run locally in your browser.
Can I sort keys or browse a tree?
Yes. Enable Sort object keys before formatting, then select Tree view to browse nested objects and arrays.
Can I validate JSON without changing the input?
Yes. Format and Minify validate into a separate output pane without changing your input. The output is reserialized; retain the original if exact number precision or duplicate keys matter.

Learn more

  • What is JSON?

    A practical introduction to JSON structure, formatting, validation, and common syntax errors.

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