Industry-Specific POS System

Context

Generic POS systems were failing a specific retail vertical. The workflows didn't match the industry's unique inventory cycles, pricing structures, and compliance requirements. The business was losing time forcing square pegs into round holes.

Constraints

• Industry-specific logic: Pricing, inventory, and reporting had to match unique business rules
• Performance: Sub-second response times for all checkout operations
• Offline capability: Needed to function during network interruptions
• Multi-location: Unified inventory and reporting across physical locations

System Design

Built as a full-stack SaaS product with:

1. Frontend — React-based terminal interface optimized for speed and touch interaction
2. Backend API — Node.js REST API with Redis caching for high-frequency operations
3. Database — PostgreSQL with carefully designed schemas for inventory tracking, transaction history, and multi-location support
4. Sync Layer — Offline-first architecture with conflict resolution for network interruptions

Key Engineering Decisions

• Used Redis for session-based cart management and real-time inventory locks
• Implemented event sourcing for transaction history to ensure auditability
• Built a custom reporting engine that generates insights from transaction patterns
• Designed the permission system for multi-role access (cashier, manager, owner)

What I'd Improve Next

• Add machine learning for demand forecasting based on historical sales data
• Build a supplier integration layer for automated reordering
• Implement a customer loyalty engine with behavioral segmentation