My-KOPKB/docs/architecture.md

To build a solid e-commerce backend using Spring Boot, you need to design it around core business domains, security, scalability, and integrations.

Here’s a structured roadmap 👇

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1️⃣ Core Functional Modules

🧑‍💼 1. User & Authentication Module

• User registration & login
• Role-based access (ADMIN, CUSTOMER, SELLER)
• JWT or OAuth2 authentication
• Password encryption (BCrypt)
• Email verification
• Forgot/reset password

Technologies

• Spring Security
• JWT
• OAuth2 (optional)
• BCryptPasswordEncoder

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2️⃣ Recommended Architecture

🔹 Layered Architecture

• Controller layer (REST APIs)
• Service layer (Business logic)
• Repository layer (Data access)
• DTO & Mapper layer (MapStruct recommended)

🔹 Database

• PostgreSQL / MySQL
• Redis (caching, cart)
• Elasticsearch (for search, optional)

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3️⃣ Important Technical Features

🔐 Security

• Spring Security
• JWT authentication
• CSRF protection
• CORS config
• Rate limiting
• Input validation

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⚡ Performance & Scalability

• Caching (Redis)
• Pagination
• Indexing DB columns
• Async processing
• Connection pooling (HikariCP)

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📡 API Design

• RESTful endpoints
• Proper HTTP status codes
• Exception handling (GlobalExceptionHandler)
• Swagger / OpenAPI documentation

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🧾 Logging & Monitoring

• Logback
• ELK stack
• Actuator
• Prometheus & Grafana

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4️⃣ Advanced / Production-Level Features

• Microservices architecture
• API Gateway
• Circuit breaker (Resilience4j)
• Kafka for order events
• Docker + Kubernetes
• CI/CD pipeline
• Cloud deployment (AWS/GCP/Azure)

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5️⃣ Suggested Database Entities

Basic Entities:

• User
• Role

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6️⃣ Tools & Dependencies

Spring Boot Starters:

• spring-boot-starter-web
• spring-boot-starter-data-jpa
• spring-boot-starter-security
• spring-boot-starter-validation
• spring-boot-starter-actuator

Other:

• Lombok
• MapStruct
• Flyway or Liquibase
• Redis
• Docker

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7️⃣ Typical Development Roadmap

1. Setup project

2. Configure DB

3. Implement User & Security

4. Add caching

5. Add logging & monitoring

6. Deploy

   ┌───────────────┐
   │   Keycloak    │
   └──┬─────────┬──┘
   

PKCE ──┘ └── OIDC code flow (mobile) (BFF callback) │ │ ┌────▼───┐ ┌───▼────┐ │ Mobile │ │ BFF │ ← Spring app, holds session └────┬───┘ └───┬────┘ │ Bearer │ Bearer (server-attached) └──────┬──────┘ ▼ ┌─────────────┐ │ Resource API│ ← validates JWT via JWKS └─────────────┘