Digital Inventory Management System

Abstract

Retail shops that sell many kinds of goods under one roof, such as stationery, electronics, groceries, clothing and home appliances, find it difficult to keep an accurate record of stock. Handwritten registers and loosely maintained spreadsheets lead to stock mismatches, unnoticed stock-outs, calculation errors in bills and a lack of timely information for the owner. This paper presents the Digital Inventory Management System for a Multicategory Shop, a secure, role-based web application that unifies stock control, customer management, GST billing and reporting. The system is a full-stack JavaScript application: a React 19 front end built with Vite, a Node.js and Express REST API, and MongoDB storage with an automatic fallback to a local JSON file. An Admin maintains the product master, restocks items individually or in batches, monitors low-stock alerts with recommended reorder quantities, manages customers and membership tiers, reviews the sales ledger, prints GST tax invoices, exports a CSV inventory report and broadcasts notifications, while a Customer browses a category-wise catalogue, checks out and tracks orders and membership benefits. Passwords are hashed with salted scrypt, sessions use signed JWT (HS256) tokens, every route is guarded by role-based middleware, and prices, discount, 5% GST, invoice numbers and stock deductions are computed only on the server, with atomic stock reservation to prevent overselling. A working prototype was exercised with sample data of 20 products, 6 customers and 5 orders, and the results show an accurate, real-time and easy-to-use inventory and billing platform.

Introduction

The study presents a web-based Digital Inventory Management System (WIP) designed to simplify inventory management, billing, customer management and reporting for small and medium-sized multicategory shops.

1. Background and Objectives

Traditional shops often use handwritten registers or spreadsheets to manage stock and billing. These methods can cause stock mismatches, delayed restocking, billing errors and poor customer-data management.

The proposed system aims to:

• Maintain a centralised product database with SKU, price, quantity and stock alerts.

• Automatically update stock after every successful order.

• Prevent overselling through atomic stock reservation.

• Generate tax invoices with membership discounts and 5% GST.

• Provide secure Admin and Customer login facilities.

• Manage Silver, Gold and Platinum membership tiers.

• Generate sales reports, inventory valuation and CSV exports.

2. Literature Review and Existing System

The study draws on classical inventory management concepts such as Economic Order Quantity (EOQ), reorder points, safety stock and inventory visibility. It also uses modern software technologies, including REST architecture, Node.js, MongoDB, JSON Web Tokens (JWT) and scrypt password hashing.

Existing manual systems have several limitations:

• Inaccurate and delayed stock records.

• No automatic low-stock notifications.

• Errors in manual GST and discount calculations.

• Weak security and accountability.

• Scattered customer and membership information.

• Time-consuming preparation of sales and inventory reports.

The proposed system addresses these limitations by integrating inventory, billing, customer management and reporting into one application.

3. Proposed System and Architecture

The system provides two separate interfaces:

• Admin Dashboard: Product management, stock adjustment, low-stock alerts, customer management, membership control, sales records, invoices and reports.

• Customer Dashboard: Product browsing, category-wise shopping, cart management, order placement and invoice viewing.

It consists of six major modules: authentication and authorisation, product management, order and billing, stock control, customer and membership management, and reports and notifications.

The system uses server-side calculations to prevent customers from manipulating product prices, discounts or tax amounts. Atomic stock reservation ensures that if multiple customers attempt to purchase the last available unit, overselling is prevented.

4. Implementation and Technologies

The application is developed using a full-stack JavaScript architecture.

If MongoDB is unavailable, the system automatically switches to local JSON-file storage.

5. Billing and Inventory Calculations

The system automatically calculates the subtotal, membership discount, GST and final payable amount.

\[ S=\sum p_iq_i \]

\[ D=\frac{S\times d}{100} \]

\[ G=0.05(S-D) \]

\[ F=(S-D)+G \]

Here, \(S\) represents the subtotal, \(D\) the membership discount, \(G\) the GST and \(F\) the final payable amount.

For example, on a ?1,000 purchase with a 10% membership discount:

• Subtotal: ?1,000

• Discount: ?100

• Taxable amount: ?900

• GST (5%): ?45

• Final amount: ?945

GST is divided equally into CGST (2.5%) and SGST (2.5%).

6. Major Features and Advantages

The system provides real-time stock updates, automatic low-stock alerts, recommended reorder quantities, secure billing, customer membership benefits and management reports. The Admin dashboard displays important information such as total products, available stock, inventory valuation, daily sales, customer count and a seven-day sales trend.

It also supports batch stock adjustments, invoice generation, customer notifications and inventory CSV exports.

7. Testing and Results

The prototype was tested using sample data containing 20 products, 6 customers and 5 orders.

The testing confirmed that:

• Customer registration and role-based login worked correctly.

• Products could be added, updated and deleted.

• Stock quantities were automatically reduced after orders.

• Membership discounts and 5% GST were calculated correctly.

• Numbered tax invoices were generated.

• Low-stock alerts appeared when quantities reached the specified limits.

• Batch stock adjustment and CSV export worked successfully.

• The application continued operating through JSON-file storage when MongoDB was unavailable.

8. Limitations and Future Scope

The evaluation was conducted using a small demonstration dataset rather than a real shop operating over an extended period. Therefore, large-scale performance, long-term reliability and practical business benefits have not yet been established. Some product images also failed to display because they depended on external internet sources.

Future work should include testing with real retail businesses, larger product databases, more customers and orders, and long-term deployment to evaluate performance, reliability and scalability.

Conclusion

The Digital Inventory Management System for a Multicategory Shop brings stock control, billing, customer management and reporting into one secure web application. The Admin obtains an accurate, real-time view of stock and its value, early warnings about shortages and tools to restock quickly, while customers obtain a convenient storefront with transparent prices, discounts and invoices. Placing all critical calculations on the server, protecting every route with role checks, storing passwords as salted hashes and reserving stock atomically with rollback make the system reliable, and the JSON-file fallback makes it easy to run without a database server. The project shows that a modern open-source stack can provide an affordable inventory solution for small and medium shops. Future work includes barcode and QR scanning for faster stock entry and billing; a supplier and purchase-order module that raises orders from low-stock alerts; integration of real UPI, card and net-banking payment gateways; demand forecasting from sales history to suggest reorder quantities; batch, expiry and returns tracking; multi-branch support with stock transfers; e-mail and SMS alerts outside the application; and a mobile application with offline mode.

References

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Copyright

Copyright © 2026 Mrs. C. Akshaya, RAKESH M, Santhosh Kumar M, Tamilselvan M. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.