FormatForge

JSON Validator

Validate your JSON syntax instantly. Find errors with precise line numbers, get helpful suggestions, and auto-fix common mistakes. 100% free and secure.

JSON Input

How to Validate JSON

  1. Paste your JSON data in the input area, or load a sample
  2. Click the "Validate" button
  3. View validation results with detailed error messages
  4. Use "Auto-Fix" to automatically repair common errors
  5. Copy the formatted, valid JSON

Features

  • Precise error location with line and column numbers
  • Auto-fix for common JSON errors
  • Helpful suggestions to fix problems
  • JSON statistics (lines, characters, depth, keys)
  • 100% client-side - your data stays private
  • Syntax highlighting with error indicators

Common JSON Errors We Detect

Trailing Commas

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

The comma after 30 is not allowed in JSON

Single Quotes

{'name': 'John'}

JSON requires double quotes, not single quotes

Unquoted Keys

{name: "John"}

Property names must be in double quotes

Frequently Asked Questions

What is a JSON Validator?

A JSON Validator checks if your JSON data follows the correct syntax rules. It identifies errors like missing commas, unquoted keys, trailing commas, and other common mistakes, showing exactly where the problem is.

What common JSON errors can be detected?

Common errors include: trailing commas, missing commas between elements, single quotes instead of double quotes, unquoted property names, missing closing brackets/braces, and invalid escape sequences.

Can the validator fix my JSON automatically?

Yes! Our validator can automatically fix many common errors like trailing commas, single quotes, and unquoted keys. When a fix is available, you'll see an 'Auto-Fix' button to apply the correction.

Is my JSON data secure?

Absolutely. All validation happens directly in your browser - your data is never sent to any server. Your JSON stays completely private and secure.

What's the difference between JSON and JSON5?

Standard JSON is strict: it requires double quotes, no trailing commas, and no comments. JSON5 is an extension that allows single quotes, trailing commas, and comments. Our validator checks against standard JSON.

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