FlashCart – Manage Flash Sales

FlashCart is a backend system designed for limited edition product drops. It handles high traffic, real time inventory and safe checkout using Redis.

The project demonstrates real world backend concepts such as:

• Redis caching
• MongoDB persistence
• JWT authentication
• Role based access (Admin/User)
• Dockerized microservices

Tech Stack

• Node.js
• Express.js
• TypeScript
• MongoDB
• Redis
• JWT Authentication
• Docker & Docker Compose

Project Structure

flash-cart/
├── src/
│   ├── controllers/
│   ├── routes/
│   ├── models/
│   ├── middlewares/
│   ├── config/
│   ├── types/
│   ├── app.ts
│   └── server.ts
├── docker-compose.yml
├── Dockerfile
├── tsconfig.json
├── package.json
└── README.md

Installation & Local Usage

1. Clone the repository

git clone https://github.com/km-saifullah/flash-cart.git
cd flash-cart

2. Install dependencies

npm install

3. Setup environment variables

Create a .env file:

PORT=5000
MONGO_URI=mongodb://localhost:27017/flashcart
REDIS_URL=redis://localhost:6379
JWT_SECRET=flashcart_secret

4. Start MongoDB & Redis

# MongoDB
mongod

# Redis
redis-server

5. Run the project

npm run dev

API runs at:

http://localhost:5000

Docker Setup

Run entire stack

docker-compose up --build

Services:

• API → Node.js
• MongoDB → Database
• Redis → Cache & inventory

API Endpoints Overview

1. Authentication

Method	Endpoint	Description
POST	/api/v1/auth/signup	Register new user
POST	/api/v1/auth/login	Login User

2. Products (MongoDB + Redis Cache)

Method	Endpoint	Description
GET	/api/v1/products	Get all products
GET	/api/v1/products/:id	Get product by ID (Redis first)
POST	/api/v1/products	Admin only: create product
GET	/api/v1/products/trending	Top 3 most viewed products

3. Flash Sale (Redis)

Method	Endpoint	Description
POST	/api/v1/sales/start/:id	Push stock from Mongo to Redis
GET	/api/v1/sales/stock/:id	Get real time stock
POST	/api/v1/sales/reserve/:id	Reserve stock using Redis

4. Orders

Method	Endpoint	Description
POST	/api/v1/orders	Create order after reservation
GET	/api/v1/orders	View user orders
DELETE	/api/v1/orders/:id	Cancel order & restore stock

How the APIs Work

• Admin creates product → stored in MongoDB

• Admin starts sale → stock pushed to Redis

• Users reserve stock

• Successful reservation → order saved in MongoDB

• Cancel order → Redis stock increment + Mongo update

• Product views tracked → Redis Sorted Set

Security Features

• JWT authentication
• Role‑based authorization
• Redis atomic inventory handling
• Admin only protected routes

License

This project is licensed under the MIT License

Conclusion

FlashCart demonstrates how to design a scalable, production ready backend capable of handling flash sales with high concurrency, real time inventory and safe checkout.

Happy Coding!