Hi, I'm

Tomasz
Marzeion

Mobile Team Leader · Flutter, Android & iOS

11 years in mobile engineering, the last four leading teams. I run the iOS, Android and Flutter teams behind apps used by millions in banking, healthcare and edtech — owning architecture, delivery and the release process, and still writing code.

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Open to engineering management & senior mobile roles
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About Me

I started in native Android in 2016 — healthcare first, then banking — and moved to Flutter in 2019 as the framework matured. Since then I've shipped cross-platform products for Android, iOS, web and desktop, from early-stage startups to one of Poland's largest banks.

Since 2022 I've led mobile teams at GoStudent, Eleks, DrAnsay and now mBank, where I run the iOS and Android team behind one of the country's largest banking apps and oversee the mobile platform and its deployment process. I pair hands-on engineering with ownership of architecture, code quality and continuous delivery.

I believe good teams ship predictably: clear architecture, rigorous code review, automated pipelines — and a lead who stays close enough to the code to make the right calls.

11 Years in
Mobile
4+ Years Leading
Teams
10M+ Users
Reached
20+ Apps
Shipped

Experience

Four mobile teams led across fintech, healthcare and edtech — built on seven years of hands-on Flutter and Android engineering.

Team Leadership · 2022 — Present

Mobile Team Leader

mBank
Jul 2026 — Present Fintech

Leading the iOS and Android team behind one of the largest mobile banking applications in Poland. Responsible for the mobile platform and its deployment process end to end.

Hybrid · Warsaw, Poland Native iOS & Android 10M+ downloads

Flutter Team Lead

DrAnsay
Jan 2025 — Jul 2026 · 1 yr 6 mos Healthcare

Led a team of Flutter developers on a top-performing medical 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

Flutter Team Lead

GoStudent
Feb 2022 — Jan 2023 · 1 yr Edtech

Flutter Team Lead for cross-platform (mobile + desktop) apps at a globally recognised 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

Hands-on Engineering · 2016 — 2023

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 Consultant Part-time

AArete
Jul 2022 — Oct 2022 · 4 mos Fintech

Developed a mobile banking application for a leading UK bank with millions of downloads across iOS and Android. Key contribution: biometric verification.

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 — appointment scheduling, video consultations, lab results 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 analyses vocal input and gives real-time feedback on pitch and technique.

Remote · Lublin, Poland 25K+ downloads

Android Developer

SPEEDNET
May 2018 — May 2020 · 2 yrs Fintech

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

On-site · Gdynia, Poland 1M+ active users

Android Developer

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

Developed and enhanced Android applications for an international client base.

On-site · Gdańsk, Poland

Android Developer

SolDevelo
Mar 2016 — Mar 2017 · 1 yr Healthcare

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

On-site · Gdynia, Poland

How I Lead

What teams can expect from me as their lead.

Player-coach

I lead from inside the codebase — reviewing pull requests, pairing on hard problems and picking up the awkward tickets when the team is stretched. Credibility with engineers comes from shipping alongside them.

Own the release

Predictable releases beat heroic ones. I set up and own CI/CD, release trains and store submissions so that shipping becomes routine and incidents become rare.

Architecture for the team

Clear module boundaries, testable layers and conventions people can follow without asking. Architecture exists so the team can move fast safely — not to impress reviewers.

No surprises

Honest estimates, visible trade-offs and early warnings. Product and business partners always know where the mobile roadmap stands — and why.

Skills & Tech

Leadership & Delivery

Team leadership Mobile architecture Release management CI/CD ownership Code review Mentoring Agile delivery Stakeholder communication Cross-platform strategy

Platforms

Flutter Android iOS Web Windows macOS

Languages

Dart Kotlin Java JavaScript Python Bash

Architecture & State

BLoC Cubit Provider GetX Melos (modular) build_runner Platform channels

Testing & Quality

Widget testing Integration testing Golden tests Mockito Patrol bloc_test

CI/CD & DevOps

Fastlane Codemagic GitHub Actions GitLab CI Jenkins Travis CI Docker App Distribution

Firebase & Backend

Firestore FCM Auth Remote Config Realtime Database Dio / Retrofit WebSockets

Observability & Growth

Sentry Crashlytics Firebase Analytics AppsFlyer Braze OneSignal Customer.io

Navigation & Localisation

AutoRoute GoRouter Beamer Flutter Intl Localizely Loco

Device & Platform APIs

Google Maps Bluetooth Biometrics NFC Camera In-App Purchase SSL pinning Secure storage

Animations & Charts

Rive Lottie AnimatedBuilder fl_chart Syncfusion

AI-assisted Engineering

Claude Cursor GitHub Copilot ChatGPT Gemini

Education & Languages

Bachelor's degree · 2012 — 2015

Polish Naval Academy, Gdynia

Internal Security

Professional course

Stanford University

Mobile Security (XACS215)

Languages

English · C1 Advanced

Polish · Native

Let's Work Together

Open to engineering management and senior mobile roles — remote, full-time or contract. Based in Gdańsk, Poland.

Email tomasz@marzeion.dev
LinkedIn in/tomasz-marzeion
GitHub github.com/tmarzeion