JSON Best Practices: Write Better JSON Code

JSON (JavaScript Object Notation) is everywhere in modern web development. Whether you’re working with APIs, configuration files, or data storage, following best practices ensures your JSON is clean, valid, and maintainable.

1. Always Use Valid JSON Syntax

Invalid JSON is the #1 cause of errors. Make sure your JSON is valid by:

✅ DO

{
  "name": "John Doe",
  "age": 30,
  "isActive": true,
  "tags": ["developer", "designer"]
}

❌ DON’T

{
  name: "John Doe",        // Missing quotes on key
  age: 30,
  isActive: true,
  tags: ["developer", "designer"],  // Trailing comma
}

Common mistakes:

• Missing quotes around keys
• Using single quotes instead of double quotes
• Trailing commas after last element
• Comments (JSON doesn’t support comments!)

2. Use Proper Indentation

Readable JSON is maintainable JSON. Use consistent indentation:

{
  "user": {
    "id": 123,
    "profile": {
      "name": "Alice",
      "email": "[email protected]",
      "preferences": {
        "theme": "dark",
        "notifications": true
      }
    }
  }
}

Tip: Use 2 or 4 spaces for indentation. Be consistent across your project!

3. Choose Meaningful Key Names

Use clear, descriptive key names that follow a consistent convention:

✅ Good

{
  "userId": 42,
  "firstName": "John",
  "lastName": "Doe",
  "emailAddress": "[email protected]",
  "isEmailVerified": true,
  "createdAt": "2025-11-08T10:30:00Z"
}

❌ Bad

{
  "uid": 42,
  "fn": "John",
  "ln": "Doe",
  "email": "[email protected]",
  "verified": true,
  "ts": "2025-11-08T10:30:00Z"
}

Naming conventions:

• camelCase: Most common (recommended for JavaScript/TypeScript)
• snake_case: Common in Python APIs
• PascalCase: Less common, but used in some .NET APIs

4. Use Appropriate Data Types

JSON supports several data types. Use the right one for your data:

{
  "string": "Hello World",
  "number": 42,
  "float": 3.14159,
  "boolean": true,
  "null": null,
  "array": [1, 2, 3],
  "object": {
    "nested": "value"
  }
}

⚠️ Important

• Don’t use strings for numbers: "age": 30 not "age": "30"
• Don’t use strings for booleans: "active": true not "active": "true"
• Use null for missing values, not empty strings

5. Keep Arrays Consistent

All items in an array should have the same structure:

✅ Good

{
  "users": [
    { "id": 1, "name": "Alice", "role": "admin" },
    { "id": 2, "name": "Bob", "role": "user" },
    { "id": 3, "name": "Carol", "role": "moderator" }
  ]
}

❌ Bad

{
  "users": [
    { "id": 1, "name": "Alice", "role": "admin" },
    { "id": 2, "fullName": "Bob Smith" },  // Different structure!
    { "userId": 3, "name": "Carol" }       // Different keys!
  ]
}

6. Limit Nesting Depth

Too much nesting makes JSON hard to read and maintain. Try to keep it to 3-4 levels maximum:

✅ Reasonable

{
  "company": {
    "departments": {
      "engineering": {
        "teams": ["frontend", "backend", "devops"]
      }
    }
  }
}

❌ Too Deep

{
  "level1": {
    "level2": {
      "level3": {
        "level4": {
          "level5": {
            "level6": {
              "data": "This is too deep!"
            }
          }
        }
      }
    }
  }
}

7. Use ISO 8601 for Dates

Always use ISO 8601 format for dates and timestamps:

{
  "createdAt": "2025-11-08T14:30:00Z",
  "updatedAt": "2025-11-08T14:30:00+00:00",
  "dateOnly": "2025-11-08"
}

8. Validate Your JSON

Always validate JSON before using it in production. Use tools like:

• datafmt.com JSON Validator - Instant online validation
• JSON Schema - Define and validate structure
• ESLint - Validate JSON files in your codebase

9. Minify for Production

Remove whitespace and indentation for production to reduce file size:

Development (formatted):

{
  "name": "DataFmt",
  "version": "1.0.0",
  "features": ["formatter", "validator"]
}

Production (minified):

{"name":"DataFmt","version":"1.0.0","features":["formatter","validator"]}

Use our JSON Minifier to minify your JSON instantly!

10. Consider JSON Schema

For complex APIs, use JSON Schema to validate structure:

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "name": {
      "type": "string",
      "minLength": 1
    },
    "age": {
      "type": "number",
      "minimum": 0,
      "maximum": 150
    },
    "email": {
      "type": "string",
      "format": "email"
    }
  },
  "required": ["name", "email"]
}

Tools to Help You

Use datafmt.com for all your JSON needs:

• ✅ Format JSON with proper indentation
• ✅ Validate JSON syntax
• ✅ Minify for production
• ✅ Convert to YAML and other formats
• ✅ 100% client-side (your data never leaves your browser!)

Conclusion

Following these best practices will help you write clean, valid, and maintainable JSON code. Remember:

1. Always validate your JSON
2. Use consistent formatting
3. Choose meaningful key names
4. Use appropriate data types
5. Keep it simple and readable

Happy coding! 🚀

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