Backend Development

Backend Development

Core Principles

• Stateless services — don't store session state in memory; use Redis or a DB
• Fail fast — validate inputs at the boundary, return errors early
• Idempotency — POST/PUT endpoints that can be called multiple times safely
• Observability — every service needs logs, metrics, and traces

API Endpoint Structure

Request Lifecycle

Request → Rate Limiting → Authentication → Authorization → Validation → Business Logic → Response

Never skip this order. Auth before business logic. Validation before processing.

Response Standards

// Success
{ "data": { ... }, "meta": { "page": 1, "total": 100 } }

// Error
{ 
  "error": { 
    "code": "VALIDATION_ERROR",
    "message": "Human-readable description",
    "details": [{ "field": "email", "issue": "Invalid format" }]
  }
}

Authentication Patterns

JWT Best Practices