How to Fix Invalid JSON

Quick Answer

Invalid JSON errors are usually caused by syntax mistakes like missing quotes, trailing commas, or mismatched brackets. Use a JSON validator to identify the exact error location, then fix the syntax issues manually or let the tool format it for you.

Common Causes of Invalid JSON

• Missing quotes - Property names and string values must be in double quotes, not single quotes
• Trailing commas - JSON doesn't allow commas after the last item in an array or object
• Unquoted property names - Unlike JavaScript, JSON requires quotes around all property names
• Mismatched brackets - Every { needs a } and every [ needs a ]
• Undefined values - JSON only supports strings, numbers, booleans, null, arrays, and objects

How to Fix Invalid JSON (3 Steps)

1. Identify the error - Copy your JSON and paste it into the JSON Formatter. The tool will show you the exact line and character where the error occurs.
2. Fix the syntax - Based on the error message, correct the issue. Common fixes include:
   • Add missing quotes around property names
   • Remove trailing commas
   • Close unclosed brackets
3. Validate the result - Paste your corrected JSON back into the validator to confirm it's now valid. The tool will also format it with proper indentation.

Example: Fixing a Common Error

Invalid JSON:

{
  name: 'John',    // Missing quotes, single quotes
  age: 30,         // Trailing comma below
}

Valid JSON:

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