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Free JSON Validator Online 2026

Validate JSON syntax online. Check for errors, find issues, and fix JSON formatting problems instantly.

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What is JSON Validation?

JSON validation checks if your JSON data follows the correct syntax rules. Valid JSON must have properly matched brackets, quoted strings, correct comma placement, and valid data types.

Common JSON Errors

  • Missing Commas: Forgot comma between properties
  • Trailing Commas: Extra comma after last property (invalid in JSON)
  • Single Quotes: JSON requires double quotes, not single
  • Unquoted Keys: Property names must be in double quotes
  • Unclosed Brackets: Missing closing ] or }

Why Validate JSON in 2026?

Development

  • Debug API responses quickly
  • Fix configuration file errors
  • Validate before deployment
  • Catch syntax errors early

Data Quality

  • Ensure data integrity
  • Prevent import/export errors
  • Validate user inputs
  • Test JSON generators

How to Fix Invalid JSON

Step 1: Identify the Error

Our validator shows the exact line and column where the error occurs

Step 2: Try Auto-Fix

Click the "Try Auto-Fix" button to automatically correct common issues

Step 3: Manual Correction

If auto-fix doesn't work, manually correct based on the error message

Step 4: Re-validate

Click "Validate JSON" again to ensure all issues are fixed

Example: Common Fixes

Invalid (single quotes):
{"name": 'John'}
Valid (double quotes):
{"name": "John"}

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