E-Commerce Microservices Platform

A full-stack e-commerce application built with Spring Boot 4, Spring Cloud 2025, and a microservices architecture. The platform handles customer management, product catalog, order processing, payments, and email notifications — all orchestrated through an API Gateway with service discovery.

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Architecture Diagram

                                    ┌─────────────────────┐
                                    │     Config Server   │
                                    │     (Port 8888)     │
                                    └──────────┬──────────┘
                                               │ Centralized Config
                                               ▼
┌──────────┐    ┌──────────────────────────────────────────────────────────┐
│  Client  │    │              Discovery Service (Eureka)                  │
│ (Browser/│    │                   (Port 8761)                            │
│   curl)  │    └──────────────────────────┬───────────────────────────────┘
└─────┬────┘                               │ Service Registry
      │                                    │
      │ HTTP                               ▼
      ▼                    ┌────────────────────────────────┐
┌─────────────┐            │         Registered Services    │
│ API Gateway │◄──────────►│                                │
│ (Port 8088) │  lb://     │  ┌───────────┐ ┌────────────┐  │
│             │  routing   │  │ Customer  │ │  Product   │  │
│ Spring Cloud│            │  │ Service   │ │  Service   │  │
│ Gateway     │            │  │ (8081)    │ │  (8082)    │  │
│ WebMVC      │            │  └───────────┘ └────────────┘  │
└─────────────┘            │                                │
                           │  ┌───────────┐ ┌────────────┐  │
                           │  │  Order    │ │  Payment   │  │
                           │  │  Service  │ │  Service   │  │
                           │  │  (8083)   │ │  (8084)    │  │
                           │  └─────┬─────┘ └──────┬─────┘  │
                           │        │              │        │
                           │  ┌─────┴──────────────┴─────┐  │
                           │  │    Notification Service  │  │
                           │  │        (8085)            │  │
                           │  └──────────────────────────┘  │
                           └────────────────────────────────┘
                                          │
              ┌───────────────────────────┼───────────────────────────┐
              ▼                           ▼                           ▼
   ┌──────────────────┐       ┌───────────────────┐       ┌──────────────────┐
   │   PostgreSQL DB  │       │   Apache Kafka    │       │    MailDev       │
   │   (Port 5432)    │       │   (Port 9092)     │       │  SMTP (1025)     │
   │                  │       │                   │       │  Web UI (1080)   │
   │ ┌──────────────┐ │       │  Zookeeper (2181) │       └──────────────────┘
   │ │ customer DB  │ │       └───────────────────┘
   │ │ product  DB  │ │              │
   │ │ order    DB  │ │     ┌────────┴────────┐
   │ │ payment  DB  │ │     │  Kafka Topics   │
   │ └──────────────┘ │     │ • order-topic   │
   └──────────────────┘     │ • payment-topic │
                            └─────────────────┘

Request Flow

Client ──► API Gateway (8088)
               │
               ├──► /api/customer/** ──► Customer Service (8081) ──► PostgreSQL
               ├──► /api/product/**  ──► Product Service  (8082) ──► PostgreSQL
               ├──► /api/order/**    ──► Order Service    (8083) ──► PostgreSQL
               └──► /api/payment/**  ──► Payment Service  (8084) ──► PostgreSQL

Order Creation Flow

1. Client ──► POST /api/order/
2. Order Service ──► (Feign) ──► Customer Service   [Validate customer]
3. Order Service ──► (Feign) ──► Product Service    [Purchase & deduct stock]
4. Order Service ──► (Feign) ──► Payment Service    [Process payment]
5. Payment Service ──► (Kafka) ──► Notification Service [Send email]
6. Order Service ──► (Kafka) ──► Notification Service   [Order confirmation email]

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Tech Stack

Layer	Technology
Language	Java 21
Framework	Spring Boot 4.0.2
Cloud	Spring Cloud 2025.1.0
API Gateway	Spring Cloud Gateway Server WebMVC
Service Discovery	Netflix Eureka
Config Management	Spring Cloud Config Server (native)
Inter-Service Comm	OpenFeign (sync), Apache Kafka (async)
Database	PostgreSQL
ORM	Spring Data JPA / Hibernate
API Docs	SpringDoc OpenAPI (Swagger UI)
Tracing	Zipkin + Micrometer Brave
Email	MailDev (development SMTP)
Containerization	Docker & Docker Compose

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Services

Infrastructure Services

Service	Port	Description
Config Server	8888	Centralized configuration for all services using native file-based profiles
Discovery Service	8761	Eureka server for service registration and discovery
API Gateway	8088	Single entry point; routes requests to downstream services via load balancer

Business Services

Service	Port	Description
Customer Service	8081	CRUD operations for customer management
Product Service	8082	Product catalog and category management, stock tracking
Order Service	8083	Order creation, orchestrates customer validation, product purchase, and payment
Payment Service	8084	Payment processing, sends Kafka notifications on success
Notification Service	8085	Consumes Kafka events and sends email notifications via MailDev

Infrastructure Components

Component	Port	Description
PostgreSQL	5432	Shared database server with separate databases per service
Kafka	9092	Message broker for async event-driven communication
Zookeeper	2181	Kafka cluster coordination
Zipkin	9411	Distributed tracing UI
MailDev	1080 (UI) / 1025 (SMTP)	Development email server with web UI
pgAdmin	8080	PostgreSQL admin UI

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API Endpoints

Customer Service (/api/customer)

Method	Endpoint	Description
POST	/create	Create a new customer
GET	/get?id={id}	Get customer by ID
GET	/get-all	Get all customers
PUT	/update/{id}	Update customer
DELETE	/delete/{id}	Delete customer

Product Service (/api/product)

Method	Endpoint	Description
POST	/	Create a new product
GET	/all-products	Get all products
GET	/product/{id}	Get product by ID
DELETE	/product/{id}	Delete product
POST	/purchase	Purchase products (deducts stock)
POST	/category/	Create a category
GET	/category/	Get all categories
GET	/category/{categoryId}	Get category by ID

Order Service (/api/order)

Method	Endpoint	Description
POST	/	Create a new order
GET	/	Get all orders
GET	/{id}	Get order by ID

Payment Service (/api/payment)

Method	Endpoint	Description
POST	/	Process a payment

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Getting Started

Prerequisites

• Docker & Docker Compose
• Ports 5432, 8080–8088, 9092, 9411, 1025, 1080, 2181 available

Run the Platform

cd services
docker compose up -d --build

Services start in dependency order:

1. PostgreSQL, Zookeeper, Kafka, Zipkin, MailDev
2. Config Server (waits for health check)
3. Discovery Service
4. All business services + Gateway

Startup time: Allow ~2 minutes for all services to register with Eureka.

Verify Services

# Check all containers are running
docker ps

# Eureka dashboard
open http://localhost:8761

# Test gateway routing
curl http://localhost:8088/api/customer/get-all
curl http://localhost:8088/api/product/all-products
curl http://localhost:8088/api/order/

Swagger UI

Each service exposes Swagger UI for interactive API documentation:

Service	Swagger UI
Customer	http://localhost:8081/swagger-ui/index.html
Product	http://localhost:8082/swagger-ui/index.html
Order	http://localhost:8083/swagger-ui/index.html
Payment	http://localhost:8084/swagger-ui/index.html

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Sample API Usage

Create a Customer

curl -X POST http://localhost:8088/api/customer/create \
  -H "Content-Type: application/json" \
  -d '{"name": "John Doe", "email": "john@example.com"}'

Create a Category

curl -X POST http://localhost:8088/api/product/category/ \
  -H "Content-Type: application/json" \
  -d '{"name": "Electronics", "description": "Electronic devices and gadgets"}'

Create a Product

curl -X POST http://localhost:8088/api/product/ \
  -H "Content-Type: application/json" \
  -d '{
    "name": "iPhone 15",
    "description": "Apple smartphone",
    "price": 999.99,
    "stock": 50,
    "categoryId": {"id": 1}
  }'

Place an Order

curl -X POST http://localhost:8088/api/order/ \
  -H "Content-Type: application/json" \
  -d '{
    "customerId": 1,
    "amount": 999.99,
    "paymentMethod": "CREDIT_CARD",
    "purchaseList": [
      {"productId": 1, "quantity": 1}
    ]
  }'

Supported payment methods: CREDIT_CARD, DEBIT_CARD, UPI, NETBANKING, VISA, STRIPE

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Monitoring & Tools

Tool	URL	Description
Eureka Dashboard	http://localhost:8761	View registered services
Zipkin	http://localhost:9411	Distributed tracing
pgAdmin	http://localhost:8080	Database management (admin@admin.com / admin)
MailDev	http://localhost:1080	View sent emails

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Project Structure

services/
├── config-server/          # Centralized configuration server
│   └── configurations/     # Property files for each service
├── discovery/              # Eureka service discovery server
├── gateway/                # API Gateway (Spring Cloud Gateway WebMVC)
├── customer/               # Customer microservice
├── product/                # Product & Category microservice
├── order/                  # Order microservice (orchestrator)
├── payment/                # Payment microservice
├── notification/           # Notification microservice (Kafka consumer)
├── postgres/
│   └── init.sql            # Database initialization script
└── docker-compose.yml      # Full platform orchestration

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License

This project is for educational and demonstration purposes.