Essential POS - Restaurant Management System

Visit Essential POS

Building a modern, scalable Point of Sale system for restaurants using cutting-edge technologies and clean architecture principles.

Project Overview

Essential POS is a full-stack restaurant management platform that I built to simplify operations for modern restaurants. The project currently serves 10+ concurrent clients and demonstrates enterprise-level architecture and infrastructure design.

Technology Stack

Frontend

• React 19 - Latest React features for optimal performance and developer experience
• Tailwind CSS v4 - Utility-first CSS framework for rapid UI development
• Shadcn UI - High-quality, accessible component library built on Radix UI
• Deployed on Vercel - Edge network for optimal frontend performance

Backend

• Node.js/Express - RESTful API architecture
• Deployed on AWS - Scalable cloud infrastructure with EC2/Lambda
• WebSockets - Real-time communication for order updates

Database & ORM

• PostgreSQL - Robust relational database hosted on Supabase
• Drizzle ORM - Type-safe database queries with excellent TypeScript support
• Supabase - Database hosting with built-in authentication and real-time subscriptions

Architecture: Screaming Architecture (Modular Design)

I implemented Screaming Architecture principles, organizing the codebase by business features rather than technical layers. This makes the application's purpose immediately clear and highly maintainable.

Module Structure

src/
├── modules/
│   ├── pos/              # Point of Sale operations
│   ├── kitchen/          # Kitchen Display System
│   ├── tables/           # Table management
│   ├── orders/           # Order processing
│   ├── inventory/        # Inventory control
│   ├── staff/            # Staff management
│   ├── reports/          # Analytics and reporting
│   └── payments/         # Payment processing
├── shared/               # Shared utilities and components
└── infrastructure/       # Database, API, external services

Benefits of Screaming Architecture

• Clear business intent - Each module represents a core business capability
• Isolated features - Modules are independent and can be developed/tested separately
• Easy onboarding - New developers immediately understand what the app does
• Scalability - Features can scale independently
• Maintainability - Changes to one module don't affect others

Infrastructure & Deployment

Frontend Infrastructure (Vercel)

• Automatic deployments from Git commits
• Edge caching for optimal global performance
• Preview deployments for every pull request
• Custom domain with SSL certificates
• Serverless functions for API routes

Backend Infrastructure (AWS)

• EC2/Lambda for compute resources
• Application Load Balancer for traffic distribution
• Auto-scaling groups to handle traffic spikes
• CloudWatch for monitoring and logging
• S3 for static assets and file storage

Database Infrastructure (Supabase)

• PostgreSQL with automatic backups
• Connection pooling for optimal performance
• Row Level Security for data protection
• Real-time subscriptions for live updates
• Automatic scaling based on usage

Development Process & Key Decisions

1. Choosing React 19

React 19 provides server components and improved concurrent rendering, perfect for a real-time POS system requiring instant updates.

2. Tailwind v4 Implementation

Migrated to Tailwind v4 for performance improvements and the new CSS-first configuration approach, reducing build times significantly.

3. Drizzle ORM Selection

Chose Drizzle over Prisma for:

• Better TypeScript inference
• Lighter bundle size
• More control over SQL queries
• Excellent migration system

4. Modular Architecture

Implemented Screaming Architecture to:

• Make business logic explicit
• Enable parallel feature development
• Simplify testing and maintenance
• Prepare for potential microservices migration

5. Multi-Cloud Strategy

• Vercel for frontend (edge network, instant deployments)
• AWS for backend (flexibility, control, enterprise features)
• Supabase for database (PostgreSQL with real-time features)

This separation allows each part to scale independently based on demand.

Technical Challenges Solved

Real-Time Order Synchronization

Implemented WebSocket connections with fallback to polling, ensuring orders appear instantly across all devices (POS terminals, kitchen screens, management dashboards).

Offline-First Capability

Built service workers and local state management to allow restaurants to continue operations during internet outages, with automatic sync when connection restores.

Multi-Tenant Architecture

Designed database schema with tenant isolation, allowing multiple restaurants to use the same infrastructure securely.

Performance Optimization

• Code splitting by route and module
• Image optimization with Next.js Image component
• Database query optimization with proper indexing
• Caching strategy for frequently accessed data

Current Metrics

• 10+ Active Clients using the system daily
• Multi-location support for restaurant chains
• 99.9% uptime through robust infrastructure
• Sub-second response times for critical operations
• Real-time synchronization across all devices

Future Enhancements

• Mobile app (React Native) for waiters
• Advanced analytics with AI insights
• Integration with third-party delivery platforms
• Inventory forecasting using ML
• Multi-currency and internationalization support