📦 Bazaar Inventory Tracking System

🧾 Overview

The Bazaar Inventory Tracking System is tailored for the growing needs of Kiryana Stores. It allows users to Add, Delete, Update, and Fetch products, as well as record stock movements (SALE or STOCK IN) and view current stock levels.

In addition, it provides real-time notifications to clients via WebSockets when stock is low, ensuring timely restocking and smooth operations.

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🛠️ Tech Stack

• NestJS – Scalable and modular backend framework
• TypeORM – Object-Relational Mapping tool for DB interactions
• PostgreSQL – Robust relational database
• Socket.IO – Real-time event-driven communication

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📐 Design Decisions

• Built with NestJS to ensure scalability, maintainability, and architectural robustness.
• Follows a Modular Layered Architecture, chosen for its:
  • ✅ Clear Separation of Concerns
  • ✅ High Scalability and Reusability
• Clean, modular codebase with ORM abstraction to allow easy replacement.
• System is optimized for scale using:
  • Redis-based caching
  • JavaScript async task queues to prevent main thread blockage.

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📌 Assumptions

• The client-side application:
  • Validates inputs and adheres to the expected API payload structure.
  • Subscribes to and handles the relevant Socket.IO events.

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🌐 API Design

• Utilizes REST APIs for a stateless, scalable, and frontend-friendly structure.
• Example Endpoints:
  • GET /product/:id
  • GET /stock-movement?date=2024/02/01&store=2
• JWT-based authentication is used for secure access.
• Versioning Strategy:
  • Each Git branch represents a different version (e.g., v1, v2, v3).

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🔁 Evolution Rationale (v1 → v3)

• v1: Basic MVP using SQLite and simple REST endpoints for CRUD operations.
• v2: Upgraded to PostgreSQL with enhanced filtering capabilities and JWT-based authentication.
• v3: Integrated WebSocket functionality for real-time low stock alerts. Implemented Redis caching and async task queues to improve scalability and system responsiveness.

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