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Case Study

Inventory Management System: From Spreadsheets to Real-Time Tracking

A barcode-scanning inventory system that replaced Excel spreadsheets with real-time stock tracking, automatic reorder alerts, and multi-warehouse support.

Client: Confidential Manufacturing Company

Timeline
18 days
Investment
$12,999
Key Result
Inventory discrepancies reduced from $180K to $12K annually

Tablet view showing a barcode scanner interface with a camera viewfinder, scanned item details card, and a stock level indicator. Desktop view shows a warehouse floor map with color-coded zones.

The Challenge

The company managed 5,000+ SKUs across 3 warehouses using shared Excel files on a network drive. When a warehouse worker pulled items, they were supposed to update the spreadsheet, but often forgot or entered wrong quantities. Monthly physical counts consistently revealed $15K in discrepancies — items that were supposedly in stock but weren't, leading to missed orders and expedited shipping costs. The spreadsheet had grown to 47 tabs over 8 years, was slow to open, and crashed weekly. Multiple workers editing simultaneously caused version conflicts that took hours to reconcile.

Our Approach

We replaced the spreadsheets with a mobile-first web app optimized for warehouse tablets. Workers scanned barcodes using the device camera (no dedicated hardware needed), and the system immediately updated stock levels. Every scan created an immutable transaction record: who scanned what, when, from which location. The multi-warehouse view showed stock levels across all 3 locations with transfer capabilities. Automatic reorder alerts triggered when any SKU hit its minimum threshold, sending purchase order drafts to the procurement team. The admin dashboard showed real-time stock levels, transaction history, and discrepancy reports. We built a one-time migration tool that parsed their 47-tab Excel monolith into the new database, mapping SKU codes, descriptions, locations, and quantities.

What We Built

Mobile-first barcode scanning via device camera (no hardware needed).
Real-time stock tracking with immutable transaction audit trail.
Multi-warehouse view with inter-warehouse transfer workflow.
Automatic reorder alerts with purchase order draft generation.
Excel migration tool parsing 47-tab spreadsheet into structured data.

Delivery Timeline

Day 1-3: Foundation + Migration

Database schema, auth with PIN codes, Excel parsing tool for 47-tab spreadsheet migration.

Day 4-7: Scanning + Tracking

Camera barcode scanning, real-time stock updates, transaction audit trail.

Day 8-11: Multi-Warehouse

Warehouse views, inter-warehouse transfers, location-specific stock levels.

Day 12-14: Alerts + Admin

Reorder alerts, PO draft generation, admin dashboard with reports.

Day 15-16: Testing + Training

Warehouse floor testing, worker training, edge case handling.

Day 17-18: Launch

Production deployment, full data migration, parallel-run with spreadsheet for 1 week.

Tech Stack

Next.js
Frontend (PWA)
Hono
Backend
PostgreSQL
Database
Drizzle ORM
ORM
ZXing
Barcode Scanning
Resend
Email
Railway
Hosting

Architecture

frontend

Next.js PWA optimized for warehouse tablets with camera barcode scanning.

backend

Hono on Railway with Drizzle ORM on PostgreSQL.

auth

Better Auth with warehouse-specific PIN codes for quick worker login.

data

PostgreSQL with full transaction history. Immutable audit log.

notifications

Slack alerts for low stock. Email PO drafts to procurement.

Security

audit

Every inventory change logged with user, timestamp, location, and quantity delta.

rbac

Worker (scan only), Supervisor (scan + transfer), Admin (full access + reports).

monitoring

Real-time discrepancy detection. Alert on unusual patterns.

backups

Hourly database snapshots. Point-in-time recovery capability.

The Results

Annual inventory discrepancies
$180,000$12,000
Monthly physical count time
3 days (all warehouses)4 hours (spot checks only)
Stockout incidents per quarter
232
We lost $180K last year to inventory errors. This system paid for itself in the first month. Workers love it because scanning is faster than typing into a spreadsheet, and I love it because I can finally trust the numbers.
Robert Chen
Warehouse Director

Key Takeaways

Camera-based barcode scanning eliminates the need for dedicated scanning hardware. Modern phone and tablet cameras handle standard barcodes with 99%+ accuracy.

Immutable transaction logs are worth their weight in gold. When a discrepancy appears, you can trace exactly what happened, when, and who was involved.

PIN-based auth for warehouse workers is critical. Nobody wants to type an email and password with gloves on. A 4-digit PIN gets them scanning in 2 seconds.

Deliverables

Full source code (PWA)Barcode scanning moduleExcel migration toolReorder alert systemWorker and admin training

FAQ

Frequently Asked Questions

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