🛒 CartFlow — High-Performance E-Commerce Order Management Platform

A production-grade order management system built with Java, Spring Boot, Kafka, and React.

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📌 What is CartFlow?

CartFlow is a full stack e-commerce order management platform that handles the complete order lifecycle — from cart management to real-time order tracking. Built with a distributed, event-driven architecture using Apache Kafka for async processing and Redis for high-performance caching.

Key capabilities:

• 🛒 Cart Management — add, remove, update quantities with Redis-backed session storage
• 💳 Checkout Processing — order placement with inventory validation
• 📦 Order Tracking — real-time order status updates via Kafka event streaming
• 🔔 Event-Driven Notifications — async order and inventory events via Kafka
• 📊 Admin Dashboard — React-based order management and inventory overview
• 🐳 Fully Containerised — runs anywhere with Docker Compose

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🏗️ Architecture

┌─────────────────────────────────────────────────────────┐
│                     React Frontend                       │
│     Cart · Checkout · Order Tracking · Admin Dashboard  │
└─────────────────────┬───────────────────────────────────┘
                      │ REST API (HTTP)
┌─────────────────────▼───────────────────────────────────┐
│                  Spring Boot Backend                     │
│                                                         │
│  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐  │
│  │ Cart Service│  │Order Service │  │Inventory Svc  │  │
│  │   (Redis)   │  │  (Postgres)  │  │  (Postgres)   │  │
│  └──────┬──────┘  └──────┬───────┘  └───────┬───────┘  │
│         │                │                  │           │
│  ┌──────▼────────────────▼──────────────────▼───────┐  │
│  │                  Apache Kafka                     │  │
│  │     order-placed · order-updated · inventory      │  │
│  └───────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────┘
         │                        │
┌────────▼────────┐    ┌──────────▼──────────┐
│   PostgreSQL    │    │       Redis          │
│  Orders + Items │    │  Cart + Sessions     │
└─────────────────┘    └─────────────────────┘

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🛠️ Tech Stack

Layer	Technology
Backend	Java 17, Spring Boot 3.x
Messaging	Apache Kafka 3.x
Caching	Redis 7.x
Frontend	React 18, Tailwind CSS
Database	PostgreSQL 15
Testing	JUnit 5, Mockito
DevOps	Docker, Docker Compose, Maven

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📁 Project Structure

cartflow/
├── backend/
│   ├── src/
│   │   ├── main/
│   │   │   ├── java/com/cartflow/
│   │   │   │   ├── controller/
│   │   │   │   │   ├── CartController.java
│   │   │   │   │   ├── OrderController.java
│   │   │   │   │   └── InventoryController.java
│   │   │   │   ├── service/
│   │   │   │   │   ├── CartService.java
│   │   │   │   │   ├── OrderService.java
│   │   │   │   │   └── InventoryService.java
│   │   │   │   ├── kafka/
│   │   │   │   │   ├── OrderProducer.java
│   │   │   │   │   └── OrderConsumer.java
│   │   │   │   ├── model/
│   │   │   │   │   ├── Cart.java
│   │   │   │   │   ├── CartItem.java
│   │   │   │   │   ├── Order.java
│   │   │   │   │   ├── OrderItem.java
│   │   │   │   │   └── Product.java
│   │   │   │   ├── repository/
│   │   │   │   │   ├── OrderRepository.java
│   │   │   │   │   ├── OrderItemRepository.java
│   │   │   │   │   └── ProductRepository.java
│   │   │   │   └── config/
│   │   │   │       ├── KafkaConfig.java
│   │   │   │       └── RedisConfig.java
│   │   │   └── resources/
│   │   │       └── application.yml
│   │   └── test/
│   │       └── java/com/cartflow/
│   │           └── service/
│   │               └── OrderServiceTest.java
│   ├── Dockerfile
│   └── pom.xml
├── frontend/
│   ├── src/
│   │   ├── components/
│   │   │   ├── Cart.jsx
│   │   │   ├── Checkout.jsx
│   │   │   ├── OrderTracking.jsx
│   │   │   └── AdminDashboard.jsx
│   │   ├── services/
│   │   │   └── api.js
│   │   └── App.jsx
│   ├── Dockerfile
│   └── package.json
└── docker-compose.yml

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⚙️ Getting Started

Prerequisites

• Java 17+
• Node.js 18+
• Docker & Docker Compose

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🐳 Run with Docker (Recommended)

# 1. Clone the repo
git clone https://github.com/Manasvi1611/cartflow.git
cd cartflow

# 2. Start everything
docker-compose up --build

App will be running at:

• Frontend → http://localhost:3000
• Backend API → http://localhost:8080
• PostgreSQL → localhost:5432
• Redis → localhost:6379
• Kafka → localhost:9092

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🔧 Run Locally (Without Docker)

Backend:

cd backend
./mvnw spring-boot:run

Frontend:

cd frontend
npm install
npm start

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📡 API Endpoints

Cart

Method	Endpoint	Description
GET	/api/cart/{sessionId}	Get cart contents
POST	/api/cart/{sessionId}/items	Add item to cart
PUT	/api/cart/{sessionId}/items/{productId}	Update item quantity
DELETE	/api/cart/{sessionId}/items/{productId}	Remove item from cart
DELETE	/api/cart/{sessionId}	Clear cart

Orders

Method	Endpoint	Description
POST	/api/orders	Place a new order
GET	/api/orders/{orderId}	Get order details
GET	/api/orders	Get all orders (admin)
PUT	/api/orders/{orderId}/status	Update order status

Inventory

Method	Endpoint	Description
GET	/api/products	Get all products
GET	/api/products/{productId}	Get product details
PUT	/api/products/{productId}/stock	Update stock level

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🔀 Kafka Topics

Topic	Producer	Consumer	Purpose
order-placed	OrderService	InventoryService	Triggers stock deduction
order-updated	OrderService	NotificationService	Status change events
inventory-low	InventoryService	AdminService	Low stock alerts

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🧪 Running Tests

cd backend
./mvnw test

Test coverage target: ~70% across service and controller layers.

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🖥️ Screenshots

(Add screenshots here once UI is built)

Cart View	Order Tracking	Admin Dashboard

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🗺️ Roadmap

• Cart management with Redis session storage
• Order placement and lifecycle management
• Kafka event-driven order processing
• Inventory management with low stock alerts
• React admin dashboard
• Docker containerisation
• Payment gateway integration
• Email notifications via Kafka consumer
• Order analytics dashboard

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👤 Author

Manaswi Gautam

• LinkedIn: linkedin.com/in/manaswi-gautam
• GitHub: github.com/Manasvi1611
• Email: manaswi.gautamhs@gmail.com

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📄 License

MIT License — feel free to use and modify.