CafeCalc

CafeCalc is a cross-platform mobile application designed to provide high-precision financial utilities, including real-time currency conversion and bill tipping calculations. Developed using React Native and TypeScript, the application serves as an all-in-one tool for orchestrating multiple third-party APIs into a fluid user experience.

The application is successfully published on the Google Play Store, demonstrating a complete Software Development Life Cycle (SDLC) from initial R&D to global deployment.

External APIs & Data Integrity

The application relies on the seamless integration of several external service providers to maintain real-time data accuracy and monetization:

• Live Currency Exchange: Engineered an integration with a real-time Currency API to fetch and cache global exchange rates, ensuring users have access to accurate financial data even under offline conditions.
• RevenueCat (IAP): Implemented RevenueCat APIs to manage Google In-App Purchases and subscription logic, providing a robust and verified framework for entitlement tracking.
• Google AdMob: Integrated Google AdMob APIs for dynamic ad-banner delivery, optimizing asset loading to ensure third-party content does not impede the application's responsiveness.

State Management & Context Caching

To optimize the user experience and reduce redundant network overhead, I engineered a sophisticated state management layer:

• Context Caching: Utilized the React Context API to implement custom caching, storing financial data and user preferences locally to allow for near-instantaneous load times and full offline functionality.
• Financial Logic Engine: Developed algorithms in TypeScript to handle multi-party bill splitting and tip calculations, ensuring mathematical precision across different international currency formats.

Modular UI & Custom Theming

The front-end uses Tailwind CSS to maintain a highly maintainable and consistent design:

• Theming Engine: Designed a custom theming architecture that allows for real-time visual transitions between multiple UI presets, managed through global state and respecting system-level light/dark modes.
• Responsive Layouts: Engineered a fluid UI/UX that adapts to various screen resolutions, ensuring a native-level experience on both smartphone and tablet form factors.

Deployment & Scalability

• Production Deployment: Successfully navigated the full deployment pipeline for the Google Play Store, including the management of production-ready code signing, versioning, and store-front assets.
• Cross-Platform Scalability: While currently deployed on Android, the codebase is architected for cross-platform compatibility, with future-ready logic prepared for iOS deployment.