Free Developer Tool

JSON Formatter

Validate, beautify and minify JSON instantly. See exactly where an error is, fix common mistakes in one click, and explore nested data in a tree view.

  • Exact error line & column
  • One-click fixes
  • Tree view
  • Nothing leaves your browser

How it works

Format JSON in 4 Simple Steps

No account, no uploads. Your JSON is processed on your own device.

  1. 1

    Paste or open your JSON

    Paste into the editor, drop a .json file onto it, or open one from your device. Files up to 25 MB work.

  2. 2

    See problems instantly

    Invalid JSON shows the exact line and column with a plain-English explanation. Fix JSON repairs common mistakes in one click.

  3. 3

    Beautify, minify or explore

    Choose 2 spaces, 4 spaces or tabs, sort keys A–Z, or switch to the tree view to browse nested data and copy paths.

  4. 4

    Copy or download

    Copy the result, download it as a .json file, or send it back to the editor to keep working.

Why Use This JSON Formatter?

A validator, beautifier, minifier and viewer in one — built for developers who want answers, not ads.

Exact Error Locations

Every error comes with its line and column, a highlighted code frame and a hint — the same in every browser.

Fix JSON in One Click

Removes comments and trailing commas, converts single quotes, quotes unquoted keys and turns Python True/None into JSON.

No Silent Number Changes

Large IDs, values like 1.50 and escape sequences are kept exactly as written, instead of being rounded or rewritten.

Tree View with JSONPath

Expand and collapse nested objects, and copy the path to any value, like $.items[0].price.

Beautify, Minify & Sort

Pretty-print with your indentation of choice or minify for production — with the size change shown.

Private & Fast

Everything runs in your browser, so API keys and customer data never leave your device. Handles multi-megabyte files.

Frequently Asked Questions

Common questions about the free JSON formatter. Contact us if you need help.

What does a JSON formatter do?
It checks that your JSON is valid and rewrites it in a readable layout with consistent indentation (beautify), or strips all spaces and line breaks to make it as small as possible (minify).
Is my JSON sent to a server?
No. Parsing, formatting and fixing all happen in your browser, so API responses, tokens and customer data never leave your device. Your current input is kept only for this browser tab, so it survives a refresh.
Why is my JSON invalid?
The most common causes are a trailing comma after the last item, single quotes instead of double quotes, property names without quotes, comments, a missing comma between values, or a raw line break inside a string. The error message shows the exact line and column.
What does “Fix JSON” change?
It removes comments and trailing commas, adds missing commas, converts single-quoted strings, quotes unquoted keys, turns Python-style True, False and None (and NaN or undefined) into valid JSON, and normalizes numbers like .5 or 0x1F. A summary of every change is shown before you apply it.
Will formatting change my numbers or text?
No. Numbers and strings are written back exactly as they appear, so an ID like 12345678901234567890, a price like 1.50 or an escape like \u00e9 stays the same. Tools built on JSON.parse round integers above 9,007,199,254,740,991.
What is the difference between beautify and minify?
Beautify adds line breaks and indentation so people can read the data. Minify removes every unnecessary character so the file is smaller for APIs, configs and storage. The size change is shown under the output.
Can it handle large JSON files?
Yes. Files up to 25 MB can be opened, and multi-megabyte documents format in about a second on a typical laptop. Syntax colors switch off for very large output to keep scrolling smooth.
Does it support JSON5 or JSON with comments (JSONC)?
Standard JSON doesn’t allow comments or trailing commas, so those are flagged as errors. Fix JSON converts the common JSON5 and JSONC extras — comments, trailing commas, single quotes, unquoted keys and hex numbers — into standard JSON.

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Browse all tools

Free online JSON formatter, JSON validator, JSON beautifier and JSON minifier with exact error positions, automatic repair of trailing commas, comments and single quotes, key sorting, tree view with JSONPath, and file upload and download. Runs entirely in your browser.