JSON Formatter Online - Free JSON Validator, Beautifier & Fixer | JSONFormatterPro.dev
⚡ Fastest JSON Tool Online • Free Forever • NEW Shareable Links + History

JSON Formatter & Validator

Format, validate, minify & fix your JSON instantly. Now with shareable links, history, and URL fetching. The tool developers love.

✓ No Signup ✓ No Ads ✓ Shareable Links ✓ 100% Private
Paste your JSON below to get started

→ Input JSON

1
0 characters • 1 line Ctrl+Enter to format • Ctrl+M to minify

Output↓ 

Output will appear here...

• Click "Format" to beautify valid JSON
• Click "Smart Fix" to repair broken JSON
• Click "🔗 Share Link" to create shareable URL
0 characters • 0 lines

🛠️ Quick Conversion Tools

Why Developers Choose JSONFormatterPro

Built by developers, for developers. Every feature you need, none of the bloat.

🔗

Shareable Links NEW

Create a URL containing your JSON to share with teammates instantly.

🌐

Fetch from URL NEW

Load JSON directly from any API endpoint. No copy-pasting needed.

📜

History NEW

Your last 10 JSONs are saved locally. Never lose your work again.

📰

JSON → XML NEW

Convert JSON to XML format with proper indentation.

🔢

Line Numbers

See exactly which line has the error. Error lines are highlighted in red!

🔧

Smart Fix

Auto-fixes trailing commas, single quotes, unquoted keys, comments & more.

⚡

Blazing Fast

Instant loading. Everything runs in your browser. No server delays.

🔒

100% Private

Your JSON never leaves your browser. Zero data collection.

What Smart Fix Can Repair

Common JSON errors that our tool automatically fixes

,] → ]

Trailing Commas

Removes commas before closing brackets

'hello' → "hello"

Single Quotes

Converts single quotes to double quotes

{name: → {"name":

Unquoted Keys

Adds quotes around object keys

// comment → (removed)

Comments

Removes // and /* */ comments

undefined → null

Undefined/NaN

Converts invalid values to null

{"a":1 → {"a":1}

Missing Brackets

Adds missing closing brackets

📚 How to Use JSONFormatterPro

Get started in seconds

1

Paste Your JSON

Copy your JSON from anywhere and paste it into the input area. Line numbers appear on the left to help you locate errors.

2

Check the Status

The status bar instantly tells you if your JSON is valid or invalid. If invalid, it shows which line has the error (highlighted in red).

3

Format or Fix

If valid, click Format to beautify. If invalid, click Smart Fix to auto-repair common issues.

❓ Frequently Asked Questions

What is JSON? +
JSON (JavaScript Object Notation) is a lightweight data format used to store and exchange data. It's easy for humans to read and write, and easy for machines to parse. Example: {"name": "John", "age": 30}
How does Smart Fix work? +
Smart Fix uses pattern matching to identify and repair common JSON errors. It fixes trailing commas, converts single quotes to double quotes, adds quotes to unquoted keys, removes comments, and balances missing brackets. After fixing, it shows you a detailed report of exactly what was changed.
How do shareable links work? +
Click "Share Link" and your JSON gets compressed and encoded into the URL. Anyone with that link can open it and see your JSON instantly. The JSON is stored in the URL itself - we don't save anything on our servers.
What is the History feature? +
Every time you format JSON, it's automatically saved to your browser's local storage (last 10 entries). Click "History" to view and restore any previous JSON. This data never leaves your computer.
Can I fetch JSON from any URL? +
Yes! Click "Fetch from URL" and enter any API endpoint. Note: Some APIs may block requests from browsers (CORS). For those, you may need to use a CORS proxy or copy-paste manually.
Is my data safe? +
Yes! All processing happens 100% in your browser. History is stored locally on your device only. Shareable links encode data in the URL - we never store your JSON on any server.
What's the maximum JSON size? +
Since everything runs in your browser, the limit depends on your device's memory. Most modern browsers can handle JSON files up to 50-100MB without issues. For extremely large files, consider using a desktop tool.