🛒 Spring Boot E-commerce Backend

A robust, production-ready backend for an e-commerce platform built with Java Spring Boot and MongoDB. This API manages the complete order lifecycle—from product inventory and shopping cart management to order processing and payment integration.

🚀 Key Features

• Product Management: Create, read, and manage product inventory with persistent storage.
• Smart Shopping Cart: Persistent cart system with real-time stock validation (prevents ordering out-of-stock items).
• Order Lifecycle: Seamless conversion of Carts to Orders with state management (CREATED → PENDING → PAID).
• 💳 Payment Integration (Razorpay):
  • Full implementation of the Razorpay Java SDK.
  • Resilience Architecture: Includes a "Fail-Safe Simulation Mode" that activates if live banking credentials are unavailable or invalid (see Compliance Note below).
• Webhooks: Automated status updates via webhook listeners.

🛠️ Tech Stack

• Language: Java 17
• Framework: Spring Boot 3.0
• Database: MongoDB (NoSQL)
• Build Tool: Maven
• Payment Gateway: Razorpay SDK

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⚠️ Compliance & Simulation Note

Regarding Payment Integration: This project includes the actual production code for Razorpay integration (PaymentService.java uses RazorpayClient).

However, due to strict KYC compliance requirements for activating a live Merchant Account (which requires business documentation), the system is currently configured to operate in a Simulation Mode.

• If valid API Keys are provided, it connects to Razorpay.
• If keys are invalid or missing, it gracefully degrades to a local simulation, generating mock Transaction IDs to ensure the Order -> Payment -> Webhook flow can still be demonstrated and tested end-to-end.

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⚙️ Setup & Installation

Prerequisites

• Java 17 or higher
• Maven
• MongoDB (Running locally on port 27017)

1. Clone the Repository

git clone [https://github.com/your-username/ecommerce-backend.git](https://github.com/your-username/ecommerce-backend.git)
cd ecommerce-backend

2. Configure Database & Keys

The application expects a MongoDB instance running locally. Update src/main/resources/application.properties if needed:

spring.data.mongodb.uri=mongodb://localhost:27017/ecommerce

# Razorpay Credentials (Optional for Simulation Mode)
razorpay.key.id=YOUR_TEST_KEY_ID
razorpay.key.secret=YOUR_TEST_KEY_SECRET

3. Run the Application

mvn spring-boot:run

The server will start at http://localhost:8080.

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🔌 API Endpoints

You can test these endpoints using Postman.

Products

Method	Endpoint	Description
POST	/api/products	Create a new product
GET	/api/products	List all products

Cart

Method	Endpoint	Description
POST	/api/cart/{userId}/add	Add item to cart (Body: {productId, quantity})
GET	/api/cart/{userId}	View user's cart

Orders & Payments

Method	Endpoint	Description
POST	/api/orders/{userId}	Convert Cart to Order
POST	/api/payment/create	Initiate Payment (Returns Payment ID)
POST	/api/webhooks/simulate-success?orderId={id}	Simulation: Manually trigger successful payment
GET	/api/orders/{orderId}	Check Order Status

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📂 Project Structure

com.example.ecommerce
├── controller      # REST Controllers (API Layer)
├── dto             # Data Transfer Objects (Request/Response)
├── model           # MongoDB Documents (Entities)
├── repository      # Data Access Layer (Interfaces)
├── service         # Business Logic (Payment, Order, Cart)
└── webhook         # Webhook Listeners & Simulation

👨‍💻 Author

Vansh Submitted for E-commerce Backend Assignment