JSON Formatter & Beautifier – Free, Private, No Upload

Local No upload Private Up to 50 MB Open source (MIT)

⚡ All processing is done in your browser. Your JSON never leaves your device.

Why Use Our JSON Formatter?

Our free online JSON beautifier helps you format, validate, and minify JSON data instantly. Whether you are a developer debugging an API, a data analyst inspecting a dataset, or a student learning JSON syntax, this tool makes your JSON readable and error‑free.

  • Privacy first: All processing is local — nothing is uploaded to any server.
  • Fast & reliable: Format large JSON objects in milliseconds.
  • Developer friendly: Clean output with line numbers and key sorting.
  • Free forever: No account, no limits, no hidden charges.

More free JSON resources: JSON Validator for the exact line and column of a syntax error, JSON Minifier to compress a payload and see the bytes saved, converting JSON to CSV (and back again), comparing two JSON documents by structure, validating against a JSON Schema, querying with JSONPath, pretty-printing JSON in a terminal or in code, sorting JSON keys recursively for a clean diff, a JSON syntax cheat sheet, and JSON guides that decode the parser errors behind the messages you are most likely to hit.

How to Format JSON

  1. Paste your JSON into the input box above — an API response, a config file, a log line.
  2. Press Format, or hit Ctrl/Cmd + Enter. The document is parsed and re‑written with indentation.
  3. Choose the indent width from 1 to 20 if you need to match your project's style — changing it re‑runs the last action.
  4. Copy the result, download it as formatted.json, or switch to Minify when you want the opposite.

If the input is not valid JSON, nothing is reformatted: the parser's own error is shown instead, and the validator gives its exact line and column with the likely cause.

What Is JSON?

JSON (JavaScript Object Notation) is a text format for structured data, defined by RFC 8259 and used by almost every HTTP API, config file and document store today. It has six value types — string, number, object, array, true/false and null — and one document holds exactly one of them.

  • Objects are quoted keys mapped to values: {"port": 8080}.
  • Arrays are ordered lists of any values: [1, "two", null].
  • Nothing else is allowed: no comments, no trailing commas, no single quotes.

Because it is written by machines and read by people, almost every real workflow needs both directions: formatted for review, minified for transport. The rules and the mistakes that break parsers are listed on the JSON syntax cheat sheet.

Formatter, Beautifier, Pretty Printer or Minifier?

These four names describe two operations on opposite ends of the same spectrum, and the words get used interchangeably — which is why searching for one often lands you on a page that does another:

  • Formatting is the general term: rewrite JSON so each value sits on its own line, indented by depth. Pretty‑printing means the same thing; “pretty printer” is the name the tool world uses for the output side of it.
  • Beautifying is formatting with the extras — consistent spacing, sorted keys, sometimes syntax colouring. This page’s Sort keys and indent width are the “beautify” part of that definition.
  • Minifying is the exact reverse: delete the same whitespace to shrink the payload for transport. It is not compression — the minifier shows the byte count before and after.
  • Validating and linting answer a different question entirely: does this parse at all? Nothing here reformats a document that fails, and the validator reports where.

Because they are all the same parse‑and‑serialise step, one page can do all of it — that is what the buttons above are for. Array order is never changed by any of them: in JSON, an array’s order is data, while an object’s key order is not (syntax rules).

Frequently Asked Questions

Is this JSON formatter free?

Yes, it is completely free to use with no limits or sign‑up required.

Is my JSON data safe?

Absolutely. Your data never leaves your browser. We do not store, transmit, or share any JSON you paste.

What does this tool do?

It formats (beautifies) JSON with custom indentation, minifies it to reduce size, and validates syntax. It also shows line numbers and supports key sorting.

Can I use it offline?

Yes, once the page loads, it works entirely offline. You can even save it for offline use.

How do I format JSON?

Paste it into the box at the top of the page and press Format, or hit Ctrl/Cmd + Enter. The document is parsed and rewritten with indentation, and the indent width is yours to choose from 1 to 20.

Can I use this as a JSON validator?

Yes. Formatting, minifying and sorting all require the input to parse first, and when it does not, the parser's own error is reported. For the exact line, column and likely cause there is a validator page on this site.

Can I sort JSON keys alphabetically?

Yes. The Sort keys toggle rebuilds every object with its keys in alphabetical order, recursively through objects nested inside arrays, while array element order is left untouched.

What is the difference between formatting and minifying?

Formatting adds indentation and line breaks so people can read the data; minifying removes exactly that whitespace so machines transfer less of it. Both are reversible and neither changes the data.

Does it handle large JSON files?

Everything runs in your browser tab, so the limit is your available memory. Multi-megabyte documents can make the tab unresponsive, so split them or work with one section at a time.

How do I indent JSON with 4 spaces?

Set the Indent field to 4 before pressing Format. It accepts any width from 1 to 20, and changing it re-runs the last action, so you can switch a document between 2 and 4 spaces without pasting it again.

Does it work on JSON arrays, not just objects?

Yes. A document whose top-level value is an array formats and minifies the same way, and nested arrays inside objects are handled too. Array element order is never changed — only object keys are sorted, when you turn that option on.