{ } JSON Validator

To validate JSON online, simply paste your JSON into the text area above and click "Validate". Our tool will instantly check if your JSON is valid and show any syntax errors with line numbers. You can also upload a JSON file or load JSON from a URL.

JSON validation checks 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

Yes, completely free! JSON Validator is:

• ✅ Free forever - no paid plans or limits
• ✅ No registration or account required
• ✅ No data stored on servers (everything runs in your browser)
• ✅ Works offline once the page is loaded

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

You can validate JSON files in two ways:

• Upload: Click the "Upload" button and select your .json file
• Drag & Drop: Simply drag your JSON file onto the editor area

The file contents will be loaded automatically and you can then validate, format, or minify it.

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
• ❌ Special characters: Escape quotes with \" and backslashes with \\

JSON Schema validation goes beyond syntax checking - it validates that your JSON data conforms to a predefined structure (schema). A JSON Schema defines:

• Required fields and their data types
• Allowed values (enums, patterns, ranges)
• Nested object structures
• Array item constraints

This tool validates JSON syntax. For schema validation, you'll need a dedicated JSON Schema validator.

JSON supports six data types:

• String: "Hello World" (must use double quotes)
• Number: 42, 3.14, -17, 1e10
• Boolean: true, false
• null: null (represents empty/no value)
• Object: {"key": "value"}
• Array: [1, 2, 3]

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

To format JSON (also called "beautify" or "pretty print"):

1. Paste your JSON into the editor
2. Click the "Format" button
3. Your JSON will be reformatted with proper indentation

We use 2-space indentation by default. In JavaScript, you can format JSON using: JSON.stringify(obj, null, 2)

JSON minification removes all unnecessary whitespace (spaces, tabs, newlines) to reduce file size. Benefits include:

• Reduced bandwidth when sending JSON over networks
• Smaller storage requirements
• Faster transmission times

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

Yes! Once you've loaded this page, the JSON validator works entirely offline. You can:

• Validate JSON without an internet connection
• Format and minify JSON offline
• Upload local files and process them

All processing happens in your browser using JavaScript - no server requests are made for validation.

JSON-LD (JSON for Linked Data) is a method of encoding Linked Data using JSON. It's commonly used for:

• SEO: Adding structured data to websites for rich search results
• Schema.org: Describing products, articles, events, etc.
• APIs: Providing machine-readable metadata

JSON-LD is valid JSON, so you can validate its syntax here. For semantic validation, use Google's Rich Results Test.

No, standard JSON does not support comments. This is intentional to keep the format simple and unambiguous.

Workarounds include:

• Using a "_comment" field: {"_comment": "This is a note"}
• Using JSON5 format (non-standard extension)
• Using YAML for configuration files (supports comments)
• Keeping comments in separate documentation

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 (4 hex digits)

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

This tool can handle JSON files up to several megabytes efficiently. Practical limits:

• Recommended: Up to 5MB for best performance
• Maximum: ~10-20MB (depends on your device)
• Tree view: May be slow for very large/deeply nested JSON

For extremely large JSON files, consider using command-line tools like jq.