JSON Best Practices: Tips for Writing Better JSON

Learn essential JSON best practices to write clean, maintainable, and efficient JSON code. This guide covers naming conventions, security tips, performance optimization, and more.

1. Naming Conventions

Use camelCase for Keys

The most common convention in JSON is to use camelCase for property names, especially in JavaScript environments:

{
  "firstName": "John",
  "lastName": "Doe",
  "emailAddress": "john@example.com",
  "phoneNumber": "+1234567890"
}

Tip: Be consistent with your naming convention throughout your entire API or application. If you choose camelCase, use it everywhere.

Use snake_case for Database Integration

If your JSON directly maps to database columns, snake_case might be more appropriate:

{
  "first_name": "John",
  "last_name": "Doe",
  "email_address": "john@example.com",
  "created_at": "2025-01-20T10:00:00Z"
}

2. Data Type Best Practices

Use Appropriate Data Types

Always use the correct data type for your values:

// Good ✓
{
  "age": 25,
  "price": 19.99,
  "isActive": true,
  "tags": ["json", "tutorial"],
  "metadata": null
}

// Bad ✗
{
  "age": "25",           // Should be number
  "price": "19.99",      // Should be number
  "isActive": "true",    // Should be boolean
  "tags": "json,tutorial", // Should be array
  "metadata": "null"     // Should be null
}

Avoid Redundant Nesting

Keep your JSON structure flat when possible:

// Good ✓
{
  "userId": 123,
  "userName": "john_doe",
  "userEmail": "john@example.com"
}

// Overcomplicated ✗
{
  "user": {
    "data": {
      "information": {
        "id": 123,
        "name": "john_doe"
      }
    }
  }
}

3. Security Best Practices

Security Warning: Never include sensitive data like passwords, API keys, or tokens in plain JSON without encryption!

Don't Store Sensitive Data

Avoid including sensitive information in JSON responses:

// Bad ✗
{
  "user": {
    "id": 123,
    "email": "john@example.com",
    "password": "mypassword123",  // NEVER do this!
    "apiKey": "secret-key-xyz"    // NEVER do this!
  }
}

// Good ✓
{
  "user": {
    "id": 123,
    "email": "john@example.com",
    "hasPassword": true
  }
}

Validate All Input

Always validate JSON input before processing:

// JavaScript validation example
function validateUserData(data) {
  if (!data.email || !data.email.includes('@')) {
    throw new Error('Invalid email');
  }
  if (typeof data.age !== 'number' || data.age < 0) {
    throw new Error('Invalid age');
  }
  return true;
}

4. Performance Optimization

Minimize JSON Size

Remove unnecessary whitespace in production:

// Development (readable)
{
  "name": "John Doe",
  "age": 30,
  "city": "New York"
}

// Production (minified)
{"name":"John Doe","age":30,"city":"New York"}

Use Pagination for Large Datasets

Instead of returning all data at once, use pagination:

{
  "data": [...],
  "pagination": {
    "currentPage": 1,
    "totalPages": 10,
    "pageSize": 20,
    "totalItems": 200
  }
}

5. Error Handling

Include Clear Error Messages

Provide structured error information:

{
  "success": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid email address",
    "field": "email",
    "timestamp": "2025-01-20T10:00:00Z"
  }
}

6. Documentation and Versioning

Version Your API Responses

Include version information in your JSON responses:

{
  "version": "2.0",
  "data": {
    "users": [...]
  }
}

7. Common Mistakes to Avoid

Common Pitfalls:

Using trailing commas (not valid in JSON)
Using single quotes instead of double quotes
Forgetting to escape special characters
Using undefined or functions (not valid in JSON)
Creating circular references

Invalid JSON Examples

// Invalid: Trailing comma
{
  "name": "John",
  "age": 30,  ← Trailing comma
}

// Invalid: Single quotes
{
  'name': 'John'  ← Must use double quotes
}

// Invalid: Unescaped characters
{
  "text": "Line 1
Line 2"  ← Must escape newline
}

Summary

Following these JSON best practices will help you:

Write more maintainable and readable JSON
Improve application performance
Enhance security and reduce vulnerabilities
Make your APIs easier to use and understand
Reduce bugs and parsing errors

Try it now: Use our free JSON validator and formatter to check your JSON against these best practices!