JSON Formatter & Validator

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 has become the de facto standard for data exchange between web servers and clients, APIs, and modern applications.

JSON is built on two universal structures:

• Objects: collections of key-value pairs enclosed in curly braces {}
• Arrays: ordered lists of values enclosed in square brackets []

How to Use This JSON Formatter

1. Paste or type your JSON data into the input textarea above.
2. Click "Format JSON" to beautify and indent the data for readability.
3. Click "Minify JSON" to remove whitespace and reduce file size.
4. Click "Validate" to check if your JSON is syntactically correct.
5. Use "Copy Result" to copy the formatted output to your clipboard.

Common JSON Errors

1. Trailing Commas

Unlike JavaScript, JSON does not allow trailing commas after the last element in an object or array. {"name": "John",} is invalid; it must be {"name": "John"}.

2. Single Quotes

JSON requires double quotes for strings and keys. {'name': 'John'} is invalid. Use {"name": "John"} instead.

3. Comments

Standard JSON does not support comments. If you need comments, consider using JSON5 or YAML formats.

4. Unescaped Characters

Certain characters like double quotes, backslashes, and newlines must be escaped within JSON strings using a backslash prefix.

Why Validate JSON?

Invalid JSON can cause application crashes, API failures, and data corruption. Validating your JSON before deployment ensures that downstream systems can parse it correctly. This tool catches syntax errors instantly and points you to the exact location of the problem.

Frequently Asked Questions

Is my JSON data sent to a server?

No. All formatting and validation happens entirely in your browser using JavaScript. Your data never leaves your device, ensuring complete privacy.

What is the maximum file size supported?

This tool can handle JSON files up to several megabytes. For very large files (10MB+), processing may take a few seconds depending on your device.

Can I format JSON from a file?

Currently, you can paste JSON text directly. For file uploads, simply open the file in a text editor, copy the contents, and paste it here.

Does this tool support JSON5 or other variants?

This tool validates against standard JSON (RFC 8259). JSON5 and other relaxed variants may not pass validation even if they are valid in their respective specifications.