Overview

The E-Commerce Backend API is a production-grade backend service designed to power modern e-commerce applications. Built with a three-tier architecture (API/Service/Data), it provides a comprehensive set of endpoints for managing products, users, carts, orders, and payments with a focus on security, performance, and scalability.

✨ Features

  • 🔐 Secure Authentication: JWT-based authentication with token protection and role-based authorization
  • 👥 User Management: Account creation, profiles, and permission controls
  • 📦 Product Catalog: Comprehensive product management with searching and filtering
  • 🛒 Shopping Cart: Flexible cart functionality with real-time stock validation
  • 💳 Order Processing: End-to-end order lifecycle management
  • 💰 Payment Integration: Seamless Stripe payment processing with webhook security
  • 🚚 Shipping Management: Order tracking and status updates
  • 👑 Admin Dashboard API: Complete administrative controls with proper permission checks
  • ⚡ Performance Optimized: Redis caching and query optimization for high throughput
  • 🐳 Containerized: Docker & Docker Compose with security best practices
  • 🔒 Security Focused: Comprehensive security controls with automated vulnerability scanning

🏗️ Architecture

The e-commerce backend follows a clean, layered architecture:

Three-Tier Architecture

The API is structured with clean separation of concerns:

  1. API Layer: Handles HTTP requests/responses, input validation, and authentication
  2. Service Layer: Contains core business logic and service orchestration
  3. Data Layer: Manages database operations and data access patterns

This architecture ensures maintainability, testability, and scalability as the application grows.

Key Components

  • FastAPI Framework: High-performance asynchronous API with automatic OpenAPI documentation
  • Pydantic Models: Strong type checking and data validation
  • SQLAlchemy ORM: Database abstraction with migrations using Alembic
  • PostgreSQL: Primary database for transactional data
  • Redis: Caching layer for high-performance reads and rate limiting
  • Docker & Docker Compose: Containerization for consistent development and deployment

Core Features

Authentication & Authorization

  • JWT-based authentication system with refresh token rotation
  • Role-based access control (RBAC) with customer and administrator roles
  • OAuth2 integration with social login providers
  • Password hashing with Argon2 and secure token management

Product Catalog Management

  • Hierarchical category system with inheritance
  • Flexible product attributes and variants
  • Full-text search with ranking and faceted filtering
  • Image handling with automatic resizing and optimized delivery

Shopping Cart & Checkout

  • Persistent and guest shopping carts
  • Real-time inventory validation
  • Dynamic pricing and promotion engine
  • Tax calculation based on location and product type

Order Management

  • Order lifecycle tracking with state transitions
  • Multiple fulfillment options
  • Email notifications and webhooks for order updates
  • Returns and refund processing

Payment Processing

  • Stripe integration for credit card processing
  • PayPal integration for alternative payments
  • Secure token-based payment flow
  • Idempotent transaction handling

⚡ Performance & Scaling

The API is designed for high performance and scalability:

  • Async Endpoints: Non-blocking request handling
  • Connection Pooling: Efficient database connections with proper transaction isolation
  • Redis Caching: Dramatically reduces database load for read operations
  • Asynchronous Processing: Non-blocking operations for concurrent requests
  • Stateless Design: Enables simple horizontal scaling
  • Rate Limiting: Prevents abuse and ensures fair usage
  • Pagination: For large result sets with DoS protection
  • Background Tasks: For CPU-intensive operations with proper session management

🔧 Technology Stack

  • FastAPI: High-performance API framework with automatic OpenAPI documentation
  • SQLAlchemy: Powerful ORM for database operations with transaction safety
  • PostgreSQL: Robust relational database for production
  • SQLite: Lightweight database for development and testing
  • Pydantic: Data validation and settings management (compatible with v1 and v2)
  • JWT: Secure, stateless authentication with replay protection
  • Stripe API: Enterprise-grade payment processing with webhook security
  • Redis: High-performance caching, session management, and rate limiting
  • Alembic: Database migration tool
  • Docker & Docker Compose: Containerization with security best practices
  • WebSockets: Real-time order and notification updates

🏗️ Architecture

My e-commerce backend follows a clean, layered architecture:

┌───────────────────┐     ┌───────────────────┐     ┌───────────────────┐
│    API Layer      │     │   Service Layer   │     │    Data Layer     │
│   (Controllers)   │────>│  (Business Logic) │────>│   (Models/ORM)    │
└───────────────────┘     └───────────────────┘     └───────────────────┘
         │                                                    │
         │                                                    │
         ▼                                                    ▼
┌───────────────────┐                              ┌───────────────────┐
│     Security      │                              │     Database      │
│   (JWT, OAuth)    │                              │   (PostgreSQL)    │
└───────────────────┘                              └───────────────────┘

🔒 Security

This project implements comprehensive security measures:

  • Enhanced JWT Authentication: Secure tokens with JTI tracking, proper algorithm validation
  • Role-Based Access Control: Strict permission enforcement for user/admin operations
  • Password Security: Bcrypt hashing with high work factor (12+ rounds)
  • Rate Limiting: Protects authentication endpoints and API routes from abuse
  • Input Validation: Thorough request validation with Pydantic schema enforcement
  • SQL Injection Prevention: Parameterized queries and ORM protection
  • Security Headers: Comprehensive set including CSP, HSTS, X-Content-Type-Options

Testing & Quality Assurance

Comprehensive testing strategy ensures reliability:

  • Unit tests with pytest (90%+ coverage)
  • Integration tests for API endpoints
  • Performance tests with Locust
  • CI/CD pipeline with GitHub Actions
  • Security vulnerability scanning

Deployment

The application is containerized with Docker and can be deployed:

  • On Kubernetes clusters for enterprise scale
  • On cloud services like AWS ECS or Google Cloud Run
  • On traditional VPS with Docker Compose

📚 API Documentation

  • Auto-generated OpenAPI docs with Swagger UI
  • Comprehensive README with setup instructions
  • Architectural decision records (ADRs)
  • API usage examples with Postman collection

Once running, explore the interactive API documentation at /docs endpoint. The API follows RESTful principles with these main resources:

Resource Description
/api/auth Authentication endpoints (login, register)
/api/users User profile management
/api/products Product catalog with searching and filtering
/api/cart Shopping cart management
/api/orders Order processing and history
/api/admin Administrative operations (protected)