JSON Validation: How to Validate and Fix JSON Syntax Errors

• Double Quotes Only: All strings and keys must use double quotes. Single quotes are not allowed.
• No Trailing Commas: Commas after the last item in objects or arrays are not allowed.
• Quoted Keys: All object keys must be enclosed in double quotes.
• Valid Data Types: JSON supports strings, numbers, booleans, null, objects, and arrays.
• No Comments: JSON does not support comments or any other non-data content.
• Proper Escaping: Special characters in strings must be escaped with backslashes.
• Matching Brackets: All opening brackets, braces, and quotes must have matching closing characters.

{
  "name": "John Doe",
  "age": 30,
  "email": "john@example.com",
  "active": true,
  "tags": ["developer", "json"],
  "address": {
    "city": "New York",
    "country": "USA"
  }
}

JavaScript:

try {
  const data = JSON.parse(jsonString);
  console.log('Valid JSON:', data);
} catch (error) {
  console.error('Invalid JSON:', error.message);
}

Python:

import json

try:
    data = json.loads(json_string)
    print('Valid JSON:', data)
except json.JSONDecodeError as e:
    print('Invalid JSON:', e.msg)

• Validate Early: Always validate JSON as soon as you receive it, before processing. This prevents errors from propagating through your application.
• Use Proper Error Handling: Wrap JSON parsing in try-catch blocks and provide meaningful error messages to users.
• Format Before Saving: Use a JSON formatter to ensure consistent formatting before saving or committing JSON files.
• Validate API Responses: Always validate JSON responses from APIs before using the data. APIs can return invalid JSON due to errors or network issues.
• Use Schema Validation: For complex JSON, consider using JSON Schema to validate not just syntax but also structure and data types.
• Test Edge Cases: Test your JSON validation with edge cases like empty objects, nested structures, and very large files.
• Keep JSON Clean: Avoid adding comments or non-standard features. Keep JSON pure and valid according to the specification.
• Use Tools: Don't manually validate large JSON files. Use validation tools like our JSON Validator for accuracy and speed.