JSON Formatter

JSON Formatter - Format and Validate JSON Online

A powerful online JSON formatter and validator tool that helps you format, beautify, minify, and validate JSON data. Features syntax highlighting, error detection with precise location, and various formatting options. Perfect for developers, API testers, and anyone working with JSON data.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It's based on a subset of JavaScript and is commonly used for:

- API responses and requests
- Configuration files
- Data storage and transmission
- Web application data exchange

JSON uses key-value pairs and supports data types including strings, numbers, booleans, arrays, objects, and null.

What does this JSON Formatter do?

This tool provides three main functions:

1. Format (Beautify): Takes compressed or poorly formatted JSON and makes it readable with proper indentation and line breaks. You can choose indent size (2, 4, or 8 spaces, or tabs) and optionally sort object keys alphabetically.

2. Minify: Removes all unnecessary whitespace, line breaks, and indentation to create the smallest possible JSON string. Useful for reducing file size in production.

3. Validate: Checks if your JSON syntax is correct and identifies any errors. If errors are found, it shows the exact line and column where the problem occurs.

All functions include syntax highlighting for better readability.

How do I format JSON?

Formatting JSON is simple:

1. Paste or type your JSON in the input field
2. Select your preferred indent size (2, 4, or 8 spaces, or tab)
3. Optionally check 'Sort object keys alphabetically' if you want keys sorted
4. Click the 'Format' button
5. View the beautifully formatted JSON in the output section

The formatted JSON will have:
- Proper indentation for nested structures
- Each key-value pair on its own line
- Syntax highlighting with colors for different data types
- Easy to read and understand structure

What's the difference between Format and Minify?

Format and Minify are opposite operations:

Format (Beautify):
- Adds indentation, line breaks, and spacing
- Makes JSON human-readable
- Increases file size
- Best for development, debugging, and viewing
- Example: A 100-character minified JSON might become 300 characters when formatted

Minify:
- Removes all unnecessary whitespace and line breaks
- Makes JSON compact and machine-optimized
- Reduces file size
- Best for production, network transmission, and storage
- Example: A 300-character formatted JSON becomes 100 characters when minified

Use Format when you need to read or edit JSON, and Minify when you need to save space or optimize performance.

How does JSON validation work?

The JSON validator checks your JSON syntax for errors by parsing it according to the JSON specification. It validates:

- Proper use of braces { } and brackets [ ]
- Correct comma placement between elements
- Valid string formatting with double quotes
- Proper escaping of special characters
- Valid data types (string, number, boolean, null, object, array)
- No trailing commas (not allowed in JSON)
- No comments (not part of JSON spec)

If validation fails, the tool shows:
- The exact error message
- Line number where the error occurs
- Column position of the error
- Highlighted error type

This helps you quickly identify and fix syntax problems.

What does 'Sort keys alphabetically' mean?

When you enable 'Sort keys alphabetically', the tool rearranges all object keys in alphabetical order. For example:

Original:
{
"name": "John",
"age": 30,
"city": "New York"
}

With sorted keys:
{
"age": 30,
"city": "New York",
"name": "John"
}

This is useful for:
- Comparing JSON files (easier to spot differences)
- Maintaining consistent key order across files
- Generating canonical JSON representations
- Version control (reduces unnecessary diffs)

Note: Sorting is applied recursively to all nested objects.

What are common JSON errors?

Common JSON syntax errors include:

1. Missing or extra commas:
Wrong: {"a": 1, "b": 2,}
Right: {"a": 1, "b": 2}

2. Single quotes instead of double quotes:
Wrong: {'name': 'John'}
Right: {"name": "John"}

3. Unquoted keys:
Wrong: {name: "John"}
Right: {"name": "John"}

4. Trailing commas in arrays or objects:
Wrong: [1, 2, 3,]
Right: [1, 2, 3]

5. Comments (not allowed in JSON):
Wrong: {"name": "John", // this is a name}
Right: {"name": "John"}

6. Unescaped special characters in strings
7. Missing closing braces or brackets
8. Invalid data types or values

This validator helps you identify and fix all these errors.

Is my JSON data safe?

Yes, your data is completely safe and private. This tool:

- Processes all JSON entirely in your browser
- Does not send any data to our servers
- Does not store or log any of your JSON
- Works offline once the page is loaded
- Does not use any external services

You can even disconnect from the internet after loading the page and the tool will still work perfectly. Your JSON data never leaves your computer.

What are the statistics shown?

After formatting, minifying, or validating, the tool displays useful statistics:

- Characters: Total number of characters in the output
- Lines: Total number of lines in the output
- Size: File size in bytes (B), kilobytes (KB), or megabytes (MB)

These statistics help you:
- Compare file sizes before and after minification
- Estimate network transfer size
- Monitor JSON data complexity
- Optimize data structures

The size shown is the actual byte size, which may differ slightly from character count for JSON containing special Unicode characters.

Can I use this for large JSON files?

Yes, this tool can handle large JSON files efficiently. It uses optimized JavaScript parsing and doesn't have artificial size limits.

Tips for large files:
- Format large files may take a moment - be patient
- Minifying is generally faster than formatting
- Very large files (>10MB) may slow down syntax highlighting
- Consider breaking extremely large JSON into smaller chunks if possible

For files larger than 50MB, you may want to use command-line tools like jq for better performance, but this online tool works well for most use cases.

Key Features

• Format JSON with customizable indentation (2, 4, 8 spaces, or tabs)
• Minify JSON to reduce file size for production
• Validate JSON syntax with precise error location
• Syntax highlighting for better readability
• Sort object keys alphabetically
• Real-time statistics (characters, lines, size)
• Copy formatted JSON to clipboard
• Download formatted JSON as .json file
• Upload JSON files for formatting
• Dark mode support
• No file size limits
• 100% client-side processing - your data never leaves your browser
• Works offline after initial load
• Mobile-friendly responsive design