JSON Formatter & Validator

How to Use the JSON Formatter

Paste or type your raw JSON into the input textarea. Click "Format / Prettify" to add proper indentation, or "Minify" to remove all whitespace. The "Validate" button checks if your JSON is valid without reformatting it. Use "Copy Output" to copy the formatted result to your clipboard.

What Is JSON?

JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. Originally derived from JavaScript, JSON is language-independent and supported by virtually every programming language. It represents data as key-value pairs and ordered lists, making it ideal for transmitting structured data between a server and a client.

JSON Syntax Rules

Valid JSON follows strict syntax rules:

• Objects are enclosed in curly braces { } and contain key-value pairs separated by commas.
• Arrays are enclosed in square brackets [] and contain values separated by commas.
• Keys must be strings enclosed in double quotes (not single quotes).
• Values can be strings, numbers, booleans (true/false), null, objects, or arrays.
• No trailing commas are allowed after the last item in an object or array.
• No comments are allowed in standard JSON.

Common JSON Errors

When working with JSON, you may encounter these common errors:

• Missing quotes around keys: {name: "John"} is invalid; use {"name": "John"}.
• Single quotes: {'name': 'John'} is invalid; JSON requires double quotes.
• Trailing comma: {"a": 1, "b": 2,} is invalid in standard JSON.
• Unescaped special characters: Backslashes, quotes, and control characters inside strings must be escaped.

Why Format JSON?

Formatted JSON is much easier to read, debug, and understand than minified JSON. When working with API responses, configuration files, or debugging data, properly indented JSON helps you quickly identify the structure, find specific values, and spot errors.

Minified JSON, on the other hand, is ideal for production use because it reduces file size and bandwidth consumption. APIs typically send minified JSON to minimize data transfer.

JSON in Web Development

JSON is the standard format for REST APIs, configuration files (like package.json), data storage (like MongoDB documents), and inter-service communication. Understanding JSON structure is essential for any web developer, and tools like this formatter make working with JSON faster and less error-prone.

Tips for Working with JSON

• Always validate JSON received from external sources before processing it.
• Use this formatter to debug API responses — paste the response and format it for easy reading.
• When writing JSON by hand, use this tool to catch syntax errors before deploying.
• For large JSON files, minify before transmission to reduce bandwidth usage.