POS System

end-to-end development for POS system utilizing RN Expo and Go as the server

Role

Full-stack Developer /Founder

Duration

Sept 2025 - Present

Client

Family owned Shop

The Problem

The shop previously relied on handwritten invoices and cash transactions, with poorly organized products and inconsistent pricing information. Frequent power outages and unreliable internet access meant the system also had to work fully offline without disrupting daily operations.

The Solution

Built an offline-first POS mobile app using React Native to manage orders, product catalog, inventory, sales, and receipts
Designed the system to operate locally using an on-site server and iPad for daily shop operations
Implemented a dual-database approach, enabling offline usage with automatic data synchronization once internet connectivity is restored

System Design

React Native as the primary client handling all business workflows and offline operations
Go backend responsible for centralized storage of sales, receipts, product data, and pricing (sync)
React web dashboard for desktop monitoring and reporting

Challenges

Enabling reliable offline communication and synchronization between React Native devices and a Go backend using local servers and Bluetooth-connected devices
Implementing barcode scanning for fast product lookup and order creation
Managing limited mobile device storage while ensuring data integrity before server synchronization
Designing a flexible pricing system with four default pricing tiers while supporting custom customer-specific pricing