JSON

JSON (JavaScript Object Notation) is the standard data format for API communication. It's lightweight, human-readable, and easy to parse.

JSON Syntax

{
  "string": "hello",
  "number": 42,
  "float": 3.14,
  "boolean": true,
  "null": null,
  "array": [1, 2, 3],
  "object": {
    "nested": "value"
  }
}

JSON Data Types

Type	Example	Notes
String	"hello"	Double quotes required
Number	42, 3.14	No distinction between int/float
Boolean	true, false	Lowercase
Null	null	Represents absence
Array	[1, 2, 3]	Ordered list
Object	{"key": "val"}	Key-value pairs

JSON in API Communication

# Request
POST /api/users HTTP/1.1
Content-Type: application/json

{
  "name": "Alice",
  "email": "alice@example.com",
  "preferences": {
    "theme": "dark",
    "notifications": true
  }
}

# Response
HTTP/1.1 201 Created
Content-Type: application/json

{
  "id": 123,
  "name": "Alice",
  "email": "alice@example.com",
  "createdAt": "2026-08-15T10:30:00Z"
}

JSON Best Practices

1. Use consistent naming — camelCase or snake_case (pick one)
2. Always include Content-Type: application/json
3. Use ISO 8601 for dates — "2026-08-15T10:30:00Z"
4. Return meaningful error responses — Include error code and message
5. Never return sensitive data — Passwords, tokens, secrets

JSON vs XML

Feature	JSON	XML
Readability	High	Medium
Size	Smaller	Larger
Parsing	Easier	Complex
Schema	JSON Schema	XSD
API Usage	REST, GraphQL	SOAP, legacy

Key Principles

1. Follow SOLID principles
2. Write clean, readable code
3. Test thoroughly
4. Document decisions
5. Monitor in production

Implementation

• Start simple, refactor as needed
• Use established patterns
• Consider trade-offs
• Review with peers

Continuous Improvement

• Learn from incidents
• Update documentation
• Share knowledge
• Mentor others

Key Points

• Understanding JSON is essential for production systems
• Always consider scalability and maintainability
• Test thoroughly before deploying to production
• Monitor performance and set up alerting

Common Patterns

1. Validation: Always validate input at the boundary
2. Error Handling: Use structured error responses
3. Logging: Log key events for debugging
4. Testing: Unit, integration, and load tests
5. Documentation: Keep docs updated with code changes