What is JSON?

JSON (JavaScript Object Notation) is a lightweight data interchange format that's easy for humans to read and write, and easy for machines to parse and generate. It's widely used for APIs, configuration files, and data storage.

✓ Validate

Check if your JSON syntax is correct and get detailed error messages with line numbers.

📐 Format

Beautify your JSON with proper indentation for better readability.

📦 Minify

Remove whitespace and compress your JSON for smaller file sizes.

🌳 Tree View

Explore your JSON structure with an interactive collapsible tree.

Frequently Asked Questions

What is JSON validation?

JSON validation is the process of checking whether a string conforms to the JSON specification. Valid JSON must follow these rules:

Data is in name/value pairs
Data is separated by commas
Objects are enclosed in curly braces {}
Arrays are enclosed in square brackets []
Strings must use double quotes (not single quotes)
No trailing commas allowed

Why is my JSON invalid?

Common reasons for invalid JSON include:

❌ Single quotes: Use "double quotes" not 'single quotes'
❌ Trailing commas: {"a": 1,} is invalid - remove the last comma
❌ Unquoted keys: {name: "value"} is invalid - keys must be quoted
❌ Comments: JSON doesn't support // or /* */ comments
❌ Missing brackets: Ensure all { } and [ ] are properly closed

What's the difference between JSON.parse() and JSON.stringify()?

These are the two main JSON methods in JavaScript:

JSON.parse(): Converts a JSON string into a JavaScript object
JSON.stringify(): Converts a JavaScript object into a JSON string

Example:

const obj = JSON.parse('{"name":"John"}');
const str = JSON.stringify({name: "John"});

What data types does JSON support?

JSON supports six data types:

String: "Hello World"
Number: 42, 3.14, -17
Boolean: true, false
null: null (represents empty value)
Object: {"key": "value"}
Array: [1, 2, 3]

Note: JSON does not support undefined, functions, or Date objects directly.

How do I format/beautify JSON?

To format JSON means to add proper indentation and line breaks for readability. Our tool uses 2-space indentation by default.

In JavaScript, you can format JSON using:

JSON.stringify(obj, null, 2)

The third parameter (2) specifies the number of spaces for indentation.

What is JSON minification?

JSON minification removes all unnecessary whitespace (spaces, tabs, newlines) from JSON to reduce file size. This is useful for:

Reducing bandwidth when sending JSON over networks
Smaller storage requirements
Faster parsing (marginally)

Minified JSON is functionally identical to formatted JSON - only the whitespace is removed.

Is this JSON validator free?

Yes, completely free! JSON Validator is:

✅ Free forever - no paid plans
✅ No registration required
✅ No data stored on servers (everything runs in your browser)
✅ Works offline once loaded

Your JSON never leaves your browser - all processing happens locally.

Can JSON have comments?

No, standard JSON does not support comments. This is by design to keep the format simple.

Workarounds include:

Using a "_comment" field: {"_comment": "This is a note", "data": 123}
Using JSON5 format (extension that allows comments)
Using YAML instead for configuration files

What's the maximum size JSON can handle?

JSON itself has no size limit, but practical limits exist:

Browser memory: Typically 1-4GB depending on browser
API limits: Many APIs limit JSON to 1-100MB
This tool: Works well up to ~10MB; larger files may slow down

For very large JSON files, consider using streaming parsers or splitting the data.

How do I escape special characters in JSON?

Special characters in JSON strings must be escaped with a backslash:

\" - Double quote
\\ - Backslash
\n - New line
\r - Carriage return
\t - Tab
\u0000 - Unicode character

Example: {"message": "He said \"Hello\""}