Maciej Korzeniewski

As a tech lead, I led the comprehensive overhaul of the Hamilton app, completely revamping its architecture and user interface to enhance user experience and performance. This involved implementing a multi-layer reactive architecture that leverages caching mechanisms to minimize the app's reliance on Firestore reads. Leading a talented team of 3 to 6 mobile developers, I ensured seamless collaboration throughout the development process. Rigorous testing was a top priority, achieving a remarkable 100% test coverage to guarantee the app's reliability. To maintain code quality, I established GitHub pipelines that included static code analysis, formatting checks, and rigorous testing procedures before merging any code changes. I streamlined the deployment process by setting up automatic store deployment pipelines using Codemagic and employed a phased rollout strategy when launching updates. Post-release, I diligently maintained the app, addressing low-level native and memory-related issues to ensure a smooth and stable user experience.

You can find the app on Google Play here: https://play.google.com/store/apps/details?id=com.hamilton.app and on the App Store here: https://apps.apple.com/us/app/hamilton-the-official-app/id1255231.054

As a developer, I was in charge of implementing Flutter SDK in Dart, Swift, and Kotlin for the client's native SDK related to beacon scanning. I was also involved in fixing bugs in the native SDK itself. I created a demo application in Flutter that showcased the functionalities of the SDK.

I also developed pipelines to automate deployments of multiple apps that the company owns.

As a mobile developer, I created a mobile app with a polished user interface using Flutter. I designed an offline-first architecture based on Firebase Firestore. I added authentication with external providers like Google, Facebook, and Apple. I implemented a recommendation system using Firebase Dynamic Links. I included a premium subscription program using IAPs (Apple Pay and Google Pay).

I successfully implemented a premium feature within the Visible app, enabling users to seamlessly collect health-related data from Polar devices through the integration of the Polar SDK. Furthermore, I ensured the secure storage of this sensitive information within an encrypted on-device database, prioritizing user data privacy and security. To facilitate data analysis and insights, I also implemented a robust data pipeline, allowing the app to efficiently upload health-related data to our backend infrastructure. This backend, powered by a Python application running on Google Cloud Run, processes the incoming data, computes relevant health metrics, and provides users with valuable insights based on their personal health data.