Maciej Korzeniewski, Developer in Pyla, Larnaca, Cyprus
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Maciej Korzeniewski

Verified Expert  in Engineering

Mobile Developer

Pyla, Larnaca, Cyprus
Toptal Member Since
July 5, 2022

Maciej is a mobile developer who has been developing, testing, deploying, and maintaining mobile applications both for Android and iOS. He has experience collaborating with teams using the Agile framework and working with native and cross-platform frameworks like Xamarin, Flutter, and React Native. Maciej is skilled in setting up CI/CD pipelines on Jenkins and Bitrise, including automatic building, testing, and deploying to the Google Play Store and App Store.


Very Good Ventures
Flutter, Firebase, Mobile
Flutter, Firebase, Mobile
Flutter, Firebase, React Native, Xamarin, .NET Core, React, Redux, Mobile




Preferred Environment

MacOS, Slack, Flutter, Firebase, TypeScript, Node.js

The most amazing...

...thing I've done was leading and developing the app Hamilton - The Official App, available for both Android and iOS.

Work Experience

Senior Flutter Developer

2021 - 2022
Very Good Ventures
  • Led the re-architecture of the Hamilton Musical app.
  • Co-developed an open-source web project called Photobooth for the Google I/O event. It allowed people to take a photo, add assets and share it with friends on social media.
  • Co-created apps for Homethrive Inc. with incorporated video streaming using Twilio SDK.
  • Improved testing skills by providing the apps with 100% test coverage.
  • Deployed apps to the App Store and Google Play Store using phased or incremental rollout.
Technologies: Flutter, Firebase, Mobile

Mobile Developer

2020 - 2021
  • Co-developed Billy, a home budget assistant app in Flutter and Firebase.
  • Developed communication and engagement skills related to working with clients.
  • Learned how to optimize Firebase Firestore usage for minimal bills.
Technologies: Flutter, Firebase, Mobile

Mobile Developer

2016 - 2020
  • Implemented a GPS tracking module for Android in Kotlin.
  • Co-created Activity Challenges, an activity GPS tracker and game, with React Native and Redux.
  • Developed the Shell Fleet Assistant, a fleet management app in Xamarin and MvvmCross.
  • Added real-time chat functionality with React Native, Redux, and Firebase Firestore for BeautyClick, a finding beauty specialist app.
Technologies: Flutter, Firebase, React Native, Xamarin, .NET Core, React, Redux, Mobile

Hamilton – The Official App
Redesigned the architecture of the old Hamilton app, a multi-layer reactive architecture with a caching mechanism, while leading a team of 3-6 mobile developers. I also ensured the app was 100% test covered and deployed it to stores using the phased rollout technique. Finally, I was in charge of fixing low-level native, memory-related crashes.


Flutter, Redux, React Native, .NET Core


Firebase, Mobile, Xamarin


Deployment, Crash Reporting, Crash Fixing, Automated UI Testing, Code Coverage




Node.js, React



2015 - 2019

Bachelor of Engineering Degree in Computer Science

Warsaw University of Technology - Warsaw, Poland