Hi, I'm

Tomasz
Marzeion

Lead Flutter Engineer

10 years building high-impact mobile applications across healthcare, fintech, and edtech. I lead teams, own architecture, and ship products used by millions of people.

Available for remote roles & freelance
Tomasz Marzeion
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About Me

Senior Flutter Developer with 7 years of dedicated experience building cross-platform applications for Android, iOS, Web, Windows, and macOS. Started with native Android in 2016 and moved to Flutter as the ecosystem matured — never looked back.

I've taken on Team Lead roles at multiple companies, combining hands-on engineering with architecture ownership, code reviews, and end-to-end CI/CD. My work spans healthcare platforms, fintech apps, retail tools, and EdTech products — many serving hundreds of thousands to millions of users.

I write clean, testable code, care deeply about delivery pipelines, and believe good architecture is invisible when it's working.

10 Years of
Experience
7 Years in
Flutter
5+ Industries
Served
20+ Apps
Delivered

Experience

Flutter — 7 years

Flutter Team Lead

DrAnsay
Jan 2025 — Present Healthcare

Led a team of Flutter developers on a top-performing cannabis retail application in Germany. Combined hands-on development with ownership of mobile architecture and continuous delivery practices.

Remote · Berlin, Germany 250K+ downloads

Flutter Team Lead

Eleks
Oct 2023 — Jan 2025 · 1 yr 3 mos Fintech

Led end-to-end development of a mobile money transfer app (akin to Revolut) for a French client — built from scratch, architecting the entire iOS and Android codebase.

Remote · Gdańsk, Poland 200K+ downloads

Senior Flutter Developer

Idego Group
Jan 2023 — Oct 2023 · 10 mos RetailTech

Implemented a cross-platform retail management application for a Swedish client, available on iOS, Android, and the web.

On-site · Gdynia, Poland 50K+ downloads

Flutter Team Lead

GoStudent
Feb 2022 — Jan 2023 · 1 yr Edtech

Flutter Team Lead for cross-platform (mobile + desktop) apps at a globally recognized EdTech company serving 500K+ users. Led development, contributed hands-on to the codebase, and architected solutions with end-to-end CI/CD.

Remote · Vienna, Austria 500K+ users

Flutter Consultant Part-time

AArete
Jul 2022 — Oct 2022 · 4 mos Fintech

Developed a mobile banking application for a leading UK bank, achieving millions of downloads across iOS and Android. Key contributions included biometric verification implementation.

Remote · London, UK 1M+ downloads

Flutter Developer

Sii Poland
May 2020 — Feb 2022 · 1 yr 10 mos Healthcare

Developed and deployed Sweden's largest mobile healthcare application — enabling appointment scheduling, video consultations, lab result access, and prescription renewals.

On-site · Gdańsk, Poland 100K+ downloads

Flutter Developer Part-time

Vocaly
Apr 2019 — May 2020 · 1 yr 2 mos Edtech

Built an AI-driven singing learning app that analyzes vocal input and provides real-time feedback on pitch and technique.

Remote · Lublin, Poland 25K+ downloads

Android — 4 years

Android Developer

SPEEDNET
May 2018 — May 2020 · 2 yrs Fintech

Engineered Android applications including a flagship mobile app for a leading Polish bank with millions of active users.

Android Developer

Insalgo
Mar 2017 — May 2018 · 1 yr 3 mos Various

Developed and enhanced Android applications for an international client base.

Android Developer

SolDevelo
Mar 2016 — Mar 2017 · 1 yr Healthcare

Built multiple components for the OpenMRS healthcare platform: a Spring-based REST API, an Angular web app, and an Android mobile app.

Skills & Tech

Frameworks

Flutter Android Angular

Languages

Dart Kotlin Java JavaScript Python Bash

State Management

BLoC Cubit Provider GetX

Testing

Integration Testing Widget Testing Mockito Patrol Golden Testing Bloc Test

DevOps & CI/CD

Fastlane Codemagic GitHub Actions GitLab CI Jenkins Docker

Firebase

Firestore FCM Analytics Auth Remote Config Distribution

Storage & Networking

Dio Retrofit SQFlite Hive WebSockets

Platforms

Android iOS Web Windows macOS

AI Tools

Claude Cursor ChatGPT GitHub Copilot Gemini

Animations

Rive Lottie AnimatedBuilder fl_chart Syncfusion Charts

Monitoring & Analytics

Sentry Crashlytics Firebase Analytics Appsflyer Braze

Device & Platform APIs

Google Maps Bluetooth Camera NFC Biometrics In-App Purchase

Let's Work Together

Open to remote full-time positions and freelance / contract projects.