JSON Formatter & Validator

How to Format JSON Online

1. Paste your JSON data into the input box on the left.

2. Choose indentation: 2 spaces, 4 spaces, or tabs.

3. Click "Format" to beautify, or "Minify" to compress your JSON. Errors are highlighted instantly.

What is JSON?

JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. It is used by REST APIs, configuration files, databases (MongoDB, CouchDB), and nearly every modern web application. JSON is human-readable and easy to parse programmatically, making it the standard for client-server communication.

JSON Formatter Features

• Beautify JSON: Format minified or messy JSON with proper indentation and line breaks
• Validate JSON: Instantly detect syntax errors with exact line and position information
• Minify JSON: Remove whitespace to reduce JSON payload size for APIs and storage
• Custom indentation: Choose between 2 spaces, 4 spaces, or tab characters
• One-click copy: Copy formatted output to clipboard instantly

Common JSON Errors

• Trailing commas: JSON does not allow a comma after the last item in an array or object
• Single quotes: JSON requires double quotes for strings, not single quotes
• Unquoted keys: All object keys must be wrapped in double quotes
• Comments: Standard JSON does not support comments (use JSONC or JSON5 for that)

FAQ

Is this JSON validator accurate? Yes. It uses the browser's built-in JSON.parse() which follows the ECMA-404 JSON standard exactly.

Can I format large JSON files? Yes. The tool handles JSON files up to several megabytes directly in your browser with no upload needed.

What's the difference between Format and Minify? Format adds indentation and line breaks for readability. Minify removes all whitespace to produce the smallest possible output.

Is my data safe? Yes. All processing happens in your browser — your JSON data is never sent to any server.