JSON Formatter / Beautifier / Minifier

Validate, format, beautify, minify, and sort JSON data with powerful options. All processing happens in your browser.

Overview

JSON (JavaScript Object Notation) is a lightweight data-interchange format. This tool helps you work with JSON by providing validation, formatting, beautification, minification, and key sorting capabilities.

Features

🎨 Beautify / Format

Pretty-print compact JSON
Make JSON human-readable
Add proper indentation and line breaks
Multiple indentation options (2, 4, 8 spaces, or tabs)

📦 Minify / Compress

Remove all whitespace
Reduce file size
Perfect for production environments
Optimize JSON for transmission

🔄 Sort Keys

Alphabetically sort object keys
Recursive sorting through nested objects
Maintain array order
Perfect for comparing JSON files

✅ Validate

Detect syntax errors
Show error messages with details
Verify JSON structure
Check for valid formatting

📁 File Support

Load JSON files from your computer
Download formatted results
Sample JSON for testing
Character count tracking

How to Use

Formatting / Beautifying JSON

Paste or type your JSON in the Input textarea
Select indentation (2 spaces, 4 spaces, 8 spaces, or tabs)
Optionally enable "Sort keys" for alphabetical ordering
Click Format button
Formatted JSON appears in the Output area
Click Copy or Download to save

Example:

// Input (compact):
{"name":"John","age":30,"city":"NYC"}

// Output (formatted with 2 spaces):
{
  "age": 30,
  "city": "NYC",
  "name": "John"
}

Minifying JSON

Paste formatted JSON in the Input textarea
Click Minify button
Compact JSON appears in the Output area
Use Copy to clipboard or Download to file

Example:

// Input (formatted):
{
  "name": "John",
  "age": 30,
  "city": "NYC"
}

// Output (minified):
{"name":"John","age":30,"city":"NYC"}

Sorting Keys

Enter your JSON in the Input textarea
Check "Sort keys (recursive)" checkbox
Click Format or Minify
Keys are sorted alphabetically at all nesting levels

Example:

// Input:
{
  "z": 3,
  "a": 2,
  "m": {
    "y": 1,
    "x": 2
  }
}

// Output (sorted):
{
  "a": 2,
  "m": {
    "x": 2,
    "y": 1
  },
  "z": 3
}

Validating JSON

Paste JSON in the Input textarea
Click Format or Minify
If valid: Output appears
If invalid: Error message shows below input

Common Errors:

Trailing commas
Missing quotes around keys
Single quotes instead of double quotes
Unclosed brackets or braces
Invalid escape sequences

Loading Files

Click Load File button
Select a .json file from your computer
File content loads into Input textarea
Format, minify, or validate as needed

Sample Data

Click Load Sample to populate the Input with example JSON for testing the tool's features.

Indentation Options

2 Spaces (Default)

{
  "name": "John",
  "address": {
    "city": "NYC"
  }
}

When to use: Most common standard, used by Google, npm

4 Spaces

{
    "name": "John",
    "address": {
        "city": "NYC"
    }
}

When to use: Many style guides, Python developers

8 Spaces

{
        "name": "John",
        "address": {
                "city": "NYC"
        }
}

When to use: Rarely used, very visible indentation

Tabs

{
	"name": "John",
	"address": {
		"city": "NYC"
	}
}

When to use: Personal preference, some editors

Common Use Cases

1. API Response Debugging

// Messy API response:
{"status":"success","data":{"user":{"id":123,"name":"John"}}}

// Formatted for debugging:
{
  "status": "success",
  "data": {
    "user": {
      "id": 123,
      "name": "John"
    }
  }
}

2. Configuration Files

Format .json config files
Validate package.json, tsconfig.json
Clean up settings files
Prepare for version control

3. Data Comparison

// Enable "Sort keys" to compare two JSON files
// Both files will have keys in same order
// Makes diff tools more effective

4. Production Optimization

// Development: Formatted for readability
// Production: Minified to reduce size
// Use Minify button before deployment

5. Log File Analysis

Format JSON logs from applications
Make logs human-readable
Extract nested data
Debug application issues

6. Data Migration

Validate exported JSON data
Format before importing
Sort keys for consistency
Check structure integrity

Technical Details

JSON Syntax Rules

Valid JSON:

Keys must be in double quotes: "key"
String values in double quotes: "value"
Numbers: 123, 45.67, -89, 1.23e10
Booleans: true, false
Null: null
Arrays: [1, 2, 3]
Objects: {"key": "value"}

Invalid JSON:

Single quotes: {'key': 'value'} ❌
Trailing commas: {"a": 1,} ❌
Unquoted keys: {key: "value"} ❌
Comments: // comment ❌
Undefined: {"key": undefined} ❌
Functions: {"fn": function(){}} ❌

Processing Steps

Formatting:

Parse JSON string to JavaScript object
Sort keys if option enabled
Stringify with specified indentation
Display in output area

Minifying:

Parse JSON string to JavaScript object
Sort keys if option enabled
Stringify with zero indentation
Display compact result

Sorting:

Recursively traverse all objects
Sort keys alphabetically using localeCompare
Maintain original array order
Apply to all nesting levels

Size Comparison

Format	Example Size	Use Case
Minified	100 KB	Production, APIs
2 Spaces	120 KB	Standard formatting
4 Spaces	140 KB	Readable, debugging
8 Spaces	180 KB	Very readable

File Size Reduction:

Minifying can reduce size by 20-40%
Depends on original formatting
More effective with deep nesting
Removes all unnecessary whitespace

Browser Compatibility

Works in all modern browsers:

✅ Chrome / Edge (Chromium)
✅ Firefox
✅ Safari
✅ Opera
✅ Mobile browsers

Uses standard JavaScript:

JSON.parse() for parsing
JSON.stringify() for formatting
Native sorting algorithms
No external dependencies

Troubleshooting

"Unexpected token" Error

Problem: Invalid JSON syntax
Solution:

Check for trailing commas: {"a": 1,} → {"a": 1}
Use double quotes: {'a': 1} → {"a": 1}
Verify brackets match: {[}] → {[]}
Remove comments (JSON doesn't support them)

"Unexpected end of JSON input"

Problem: Incomplete JSON
Solution:

Check all braces are closed: { needs }
Verify all brackets are closed: [ needs ]
Ensure no truncated strings
Check file loaded completely

Keys Not Sorting

Problem: Sort checkbox not working
Solution:

Ensure "Sort keys (recursive)" is checked
Click Format or Minify button again
Refresh the page and try again
Note: Arrays maintain their original order

Large File Slow

Problem: Processing takes time
Solution:

Browser may have memory limits
Try smaller chunks of JSON
Close other browser tabs
Use Chrome for best performance

Copy Not Working

Problem: Copy button doesn't work
Solution:

Check browser clipboard permissions
Manually select and copy text
Try a different browser
Use Download instead

Privacy & Security

✅ Completely Private

All processing happens in your browser
No data sent to any server
Your JSON never leaves your device
No logging or tracking

✅ No Storage

Nothing is saved locally
Data cleared on page refresh
No cookies or local storage
Completely ephemeral

⚠️ Security Notes

Safe to use with sensitive data
No network requests made
Runs entirely offline-capable
View source to verify

Best Practices

✅ Do's

Format JSON before committing to version control
Minify JSON for production/APIs
Sort keys for consistent comparisons
Validate JSON before using in applications
Use 2 or 4 spaces for standard formatting
Download formatted files for backups

❌ Don'ts

Don't add comments (JSON doesn't support them)
Don't use single quotes
Don't include trailing commas
Don't assume sorted order (unless you sorted)
Don't rely on key order in old browsers
Don't forget to validate after manual edits

Keyboard Shortcuts

Ctrl/Cmd + Enter: Format JSON
Ctrl/Cmd + Shift + M: Minify JSON
Ctrl/Cmd + K: Clear all
Tab: Indent selected text (in textarea)

Examples

Example 1: API Response Formatting

// Input:
{"status":"ok","results":[{"id":1,"name":"Product A","price":29.99},{"id":2,"name":"Product B","price":39.99}]}

// Output (2 spaces, sorted):
{
  "results": [
    {
      "id": 1,
      "name": "Product A",
      "price": 29.99
    },
    {
      "id": 2,
      "name": "Product B",
      "price": 39.99
    }
  ],
  "status": "ok"
}

Example 2: Config File Cleanup

// Input (messy config):
{
"debug": true,
    "port": 3000,
"host": "localhost",
        "database": {
    "host": "db.example.com",
        "port": 5432
}
}

// Output (clean, sorted):
{
  "database": {
    "host": "db.example.com",
    "port": 5432
  },
  "debug": true,
  "host": "localhost",
  "port": 3000
}

Example 3: Nested Object Sorting

// Input:
{
  "z": 3,
  "a": {
    "y": 2,
    "b": [3, 1, 2],
    "x": 1
  },
  "m": 5
}

// Output (sorted recursively):
{
  "a": {
    "b": [3, 1, 2],
    "x": 1,
    "y": 2
  },
  "m": 5,
  "z": 3
}

Example 4: Data Types

{
  "string": "Hello, World!",
  "number": 42,
  "float": 3.14159,
  "boolean": true,
  "null": null,
  "array": [1, 2, 3],
  "object": {
    "nested": "value"
  },
  "scientific": 1.23e-10
}

Example 5: Minification Comparison

// Before (134 chars):
{
  "name": "John",
  "age": 30,
  "email": "john@example.com"
}

// After (51 chars, 62% reduction):
{"name":"John","age":30,"email":"john@example.com"}

Frequently Asked Questions

What's the difference between Format and Minify?

Format adds indentation and line breaks for readability. Minify removes all whitespace to reduce file size.

Can I sort array items?

No, only object keys are sorted. Array order is preserved to maintain data integrity.

Is sorting case-sensitive?

Yes, sorting uses localeCompare() which is case-sensitive. Uppercase letters come before lowercase.

What happens to duplicate keys?

The last occurrence wins. JSON technically doesn't allow duplicate keys, but JavaScript will keep the last value.

Can I format invalid JSON?

No, the tool requires valid JSON. It will show an error message explaining what's wrong.

How deep can nested objects be?

JavaScript typically supports 100+ levels of nesting, but very deep structures may be slow to process.

Does it handle Unicode characters?

Yes, full Unicode support including emoji and international characters.

Can I use this for YAML or XML?

No, this tool is specifically for JSON. Use our YAML ⇄ JSON converter for YAML files.

Why use this instead of a code editor?

Quick validation, one-click formatting, no setup required, works anywhere, perfect for quick tasks.

Is there a file size limit?

Browser memory is the limit (typically several MB). Very large files (>10 MB) may be slow.

Common JSON Patterns

RESTful API Response

{
  "status": "success",
  "data": {
    "id": 123,
    "attributes": {...}
  },
  "meta": {
    "timestamp": "2025-11-26T10:00:00Z"
  }
}

Package.json Structure

{
  "name": "my-app",
  "version": "1.0.0",
  "dependencies": {
    "react": "^18.0.0"
  },
  "scripts": {
    "start": "node index.js"
  }
}

Configuration File

{
  "env": "production",
  "database": {
    "host": "localhost",
    "port": 5432
  },
  "features": {
    "auth": true,
    "api": true
  }
}

Error Messages Explained

"Unexpected token"

Missing comma between properties
Extra comma at end
Wrong quote type (single vs double)
Special character not escaped

"Expected property name"

Key not in double quotes
Missing colon after key
Invalid key name

"Unexpected end of input"

Missing closing brace }
Missing closing bracket ]
Truncated file

"is not valid JSON"

Contains comments
Has trailing commas
Uses single quotes
Includes undefined or functions

Related Tools

JSON Tree Viewer - Visualize JSON structure with expandable tree
JSON Minifier - Dedicated minification tool
YAML ⇄ JSON - Convert between YAML and JSON
Text Diff Checker - Compare two JSON files

Tips & Tricks

Quick Validation

Paste any JSON and click Format. If it works, your JSON is valid!

Comparing JSON Files

Sort keys in both files
Format with same indentation
Use Text Diff Checker to compare

Creating Test Data

Use Load Sample, modify it, then download for use in tests.

Debugging API Responses

Copy response from browser DevTools, format here, analyze structure.

Version Control

Always format JSON files before committing to ensure consistent diffs.

Performance Tips

Large files: Consider processing in chunks
Many objects: Sorting may take a few seconds
Deep nesting: May slow down recursive sorting
Character count: Updated in real-time

Standards & Specifications

This tool follows:

RFC 8259: The JSON Data Interchange Format
ECMA-404: The JSON Data Interchange Syntax
JSON.org: Official JSON specification

Credits

Built with native JavaScript JSON.parse() and JSON.stringify() methods. No external libraries required for maximum privacy and performance.