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Offline-First Android POS System

Personal Completed
Summary
JAYMA is a production-ready Android Point of Sale (POS) system designed for retail environments and optimized for POS hardware such as SUNMI devices. The application is built with an offline-first architecture, allowing uninterrupted sales and inventory operations even without internet connectivity. Data automatically syncs once a connection is restored.

Many retail businesses in emerging markets experience unstable internet connectivity, which disrupts sales operations and inventory tracking. Traditional cloud-based POS systems fail when offline, leading to lost sales and inconsistent data.

I designed and built an offline-first Android POS system that:

  • Processes sales without internet access

  • Stores transactions locally using Room database

  • Syncs automatically using WorkManager when connectivity returns

  • Supports barcode scanning (hardware & camera-based)

  • Integrates receipt printing for POS hardware

  • Manages multi-warehouse inventory

  • Provides smooth checkout workflows with draft saving

The architecture ensures reliability, scalability, and maintainability using modern Android development standards.

Key Features

  • Offline-first architecture

  • Multi-warehouse inventory management

  • Barcode scanning integration

  • SUNMI printer integration

  • Background data synchronization

  • Product browsing & filtering

  • Secure and modular MVVM architecture

Impact / Results

  • Enables continuous retail operations in low-connectivity environments

  • Reduces business downtime caused by network failures

  • Provides scalable foundation for future fintech or ERP expansion

  • Demonstrates strong architectural design and hardware integration capability

Tech Stack

Kotlin, MVVM Architecture, Repository Pattern, Room Database, Retrofit, Hilt (Dependency Injection), Coroutines, WorkManager

Links & Documents
Live Project GitHub
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