JSON Formatter & Validator

Beautify, minify and validate your JSON data instantly. All processing happens in your browser — your data stays private.

📥 Input JSON

📤 Output

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. Originally derived from JavaScript, JSON has become the de facto standard for data exchange in web applications, APIs, configuration files, and databases across virtually every programming language.

JSON supports two primary structures: objects (unordered collections of key-value pairs wrapped in curly braces) and arrays (ordered lists of values wrapped in square brackets). Values in JSON can be strings, numbers, booleans (true/false), null, objects, or arrays, allowing deeply nested data structures.

How to Use This JSON Formatter

Using this tool is straightforward. Paste your raw, minified, or messy JSON into the input box and click Beautify to format it with proper indentation (2 spaces by default). Click Minify to compress your JSON by removing all unnecessary whitespace — useful for reducing payload size in APIs. The Validate button checks whether your JSON is syntactically correct and highlights the exact location of any errors.

This formatter processes everything locally in your browser using JavaScript's built-in JSON.parse() and JSON.stringify() methods. No data is ever transmitted to our servers or any third party, making it safe for use with sensitive or proprietary data.

Common JSON Errors and How to Fix Them

The most frequent JSON syntax errors include trailing commas after the last item in an object or array (which JavaScript allows but JSON does not), using single quotes instead of double quotes around strings, and forgetting to quote property names. Other common mistakes include including comments (JSON does not support comments), using undefined or NaN values, and having unescaped special characters within strings. Our validator will pinpoint the exact line and character position of these errors so you can fix them quickly.

JSON Formatting Best Practices

When working with JSON in development, use beautified (pretty-printed) JSON for readability during debugging, code reviews, and documentation. For production API responses and data storage, use minified JSON to reduce bandwidth and improve loading times. Always validate your JSON before deploying configuration files to catch syntax errors early. When dealing with large JSON files, consider using streaming parsers in your application code rather than loading the entire document into memory.

Frequently Asked Questions

Is my data safe when using this JSON formatter?
Yes. All processing happens entirely in your web browser using client-side JavaScript. Your JSON data is never sent to our servers, stored in any database, or shared with third parties. You can verify this by checking your browser's network tab while using the tool.
What is the maximum JSON size this tool can handle?
Since the tool runs in your browser, the limit depends on your device's available memory. In practice, it handles JSON files up to several megabytes without issues on modern devices. For very large files (50MB+), consider using a desktop tool or command-line utility like jq.
What is the difference between JSON and JavaScript objects?
While JSON syntax is derived from JavaScript object notation, they are not identical. JSON requires double-quoted strings for all keys and values, does not allow trailing commas, does not support comments, and cannot contain functions or undefined values. A JavaScript object is more flexible but cannot be directly transmitted as text without serialization.
Can I use this tool to validate JSON API responses?
Absolutely. Copy the raw response body from your browser's developer tools or API client (like Postman), paste it into the input area, and click Validate. The tool will confirm whether the response is valid JSON and format it for easy reading.
Does this tool support JSON5 or JSONC (JSON with comments)?
This tool validates and formats standard JSON (RFC 8259) only. JSON5 and JSONC are non-standard extensions. If your data contains comments or trailing commas, you will need to remove them first or use a dedicated JSON5 parser.
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