Why Use a JSON Validator?

Find Errors Fast

Instantly detect syntax errors, missing commas, unclosed brackets, and other common JSON mistakes.

Auto-Fix Errors

Automatically fix common errors like trailing commas, single quotes, and unquoted keys.

Precise Location

See exactly where errors occur with line numbers and character positions highlighted.

Schema Validation

Validate JSON against a JSON Schema to ensure your data structure is correct.

How to Validate JSON

1

Paste Your JSON

Paste your JSON data into the editor, drag and drop a file, or load from URL

2

Instant Validation

Your JSON is validated automatically as you type, with real-time error detection

3

Fix or Explore

Use auto-fix to correct errors, or explore valid JSON in the tree view

Common JSON Errors We Detect

Trailing Commas

{ "name": "John", "age": 30, }

JSON doesn't allow trailing commas after the last item. Our auto-fix removes them automatically.

Single Quotes

{ 'name': 'John' }

JSON requires double quotes for strings. Single quotes are invalid. We automatically convert them.

Unquoted Keys

{ name: "John" }

Object keys must be enclosed in double quotes. Unlike JavaScript, JSON doesn't allow unquoted keys.

Missing Commas

{ "name": "John" _ "age": 30 }

Multiple values must be separated by commas. We detect and highlight where commas are missing.

Unclosed Brackets

{ "items": [1, 2, 3_

Every opening bracket must have a matching closing bracket. We show exactly where the mismatch occurs.

Comments in JSON

{ // this is a comment
  "name": "John"
}

Standard JSON doesn't support comments. We can automatically strip them during auto-fix.

JSON Validator Features

Real-Time Validation

JSON is validated as you type, with instant feedback on syntax errors and their locations.

Smart Auto-Fix

Automatically repairs common errors including trailing commas, single quotes, and unquoted keys.

Line Numbers

See exact line numbers where errors occur, with error lines highlighted in red for easy identification.

JSON Schema Validation

Validate your JSON against a JSON Schema to ensure it matches your expected structure.

Tree View

Explore valid JSON in an interactive tree view with collapsible nodes and type indicators.

100% Private

All validation happens in your browser. Your JSON data never leaves your computer.

Frequently Asked Questions

What is valid JSON?

Valid JSON must follow the JSON specification (RFC 8259). It requires double quotes for strings and keys, no trailing commas, no comments, and properly nested brackets. Values can be strings, numbers, booleans, null, arrays, or objects.

Is my data secure?

Yes, absolutely. All JSON validation happens directly in your browser using JavaScript. Your data is never sent to any server. You can even disconnect from the internet after loading the page and continue validating.

Can it validate large JSON files?

Yes, JSON Purrser can handle large JSON files efficiently. The validator is optimized for performance and can process files with thousands of lines without issues.

What's the difference between JSON validation and JSON Schema validation?

JSON validation checks if your data is syntactically correct JSON. JSON Schema validation goes further - it checks if your JSON matches a specific structure defined by a schema, including required fields, data types, and constraints.

Why is my JSON showing as invalid when it works in JavaScript?

JavaScript is more lenient than strict JSON. It allows trailing commas, single quotes, unquoted keys, and comments. These are all invalid in standard JSON. Use our auto-fix feature to convert JavaScript object notation to valid JSON.

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Get instant feedback on your JSON syntax with detailed error messages and auto-fix suggestions.

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JSON Validator