Senior Flutter Engineer at LeanCode
I also build websites for Polish businessesDawid Niedźwiecki
I'm a Flutter engineer from Poznań. I build mobile apps people use every day. I've led a Flutter team, and I'm happiest where solid architecture and drama-free releases matter.
Apps I've worked on
Work
Selected work
Production apps I've built or helped build.
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Tide
Fintech platform
2025–2026
A major international fintech platform for small businesses, freelancers and sole traders in the UK, India, France and Germany, built by more than a hundred Flutter engineers in a single monorepo. I shipped Offers & Rewards features (Rewards Hub, Marketplace, deep links, monitoring), then owned the Companies House filing flows in CoSec: address changes, authentication codes and the CS01 confirmation statement.
- Flutter
- Dart
- Monorepo
- Deep links
- Analytics
- Monitoring
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Yanosik
Navigation and speed camera alerts
Yanosik S.A. · 2024–2025
Brought Flutter into Yanosik's native iOS and Android apps with add-to-app. I turned an existing Flutter app into an embeddable module, built the integration layer on the Flutter side, bootstrapped the module in both native projects and handled its dependencies in CI/CD.
- Flutter
- Add-to-app
- Method channels
- Kotlin
- Swift
- CI/CD
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Flutter Tech Summit
Conference app
LeanCode · 2025
Companion app for LeanCode's Flutter Tech Summit, with the schedule, the speakers, a venue map, talk ratings and live notifications.
- Flutter
- Push notifications
- Deep links
- Maps
- CI/CD
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Autoplac
Car classifieds
Yanosik S.A. · 2021–2025
A classifieds app for buying and selling cars that I developed and maintained for more than three years. Clean Architecture with BLoC, get_it and injectable, native code through dart:ffi and method channels, Firebase and Crashlytics in production.
- Flutter
- BLoC
- get_it
- injectable
- dart:ffi
- Firebase
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FlotisManager
Fleet management
Yanosik S.A.
Built a mobile app from scratch for fleet managers and drivers in logistics: maps on Mapbox and MapLibre, Clean Architecture with BLoC, Dio for the API, Firebase and Crashlytics, shipped through CI/CD.
- Flutter
- Mapbox
- MapLibre
- BLoC
- Dio
- CI/CD
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Dealer Apps
White-label apps for car dealers
Yanosik S.A.
White-label apps that car dealers use to manage and present their stock, built with Flutter for mobile and the web and branded for each dealer.
- Flutter
- Flutter Web
- White-label
- CI/CD
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Smart City Poznań
City services app
G-Group.dev · 2021–2022
Migrated the City of Poznań's services app to null safety (Dart 2.12), kept production releases going after the migration and added sign-in with ID.Poznań over OpenID Connect, working directly with the client.
- Flutter
- Null safety
- OpenID Connect
Side project
Built in one day
Clocker
Time tracking for Jira Cloud
Clocker puts your daily goal into Jira's Log time dialog, so you see how much is left while you log it. A weekly timesheet and monthly reports sit right next to it, and every entry is a plain Jira worklog, so nothing gets locked in.
- Runs entirely on Atlassian Forge, with no servers of its own
- Speaks all 26 languages Jira offers
- Light and dark themes that follow Jira
- Available on the Atlassian Marketplace
Experience
From navigation to fintech
Commercial Flutter since 2021, with teaching on the side for the first few years.
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LeanCode 2025 – now : Senior Flutter Engineer, May 2025 – now -
Tide 2025–2026 : Mobile Software Engineer (Flutter), Offers & Rewards, Jun 2025 – Jan 2026; Mobile Software Engineer (Flutter), CoSec, Jan 2026 – Jul 2026 -
Yanosik S.A. 2021–2025 : Junior Flutter Developer, Dec 2021 – Jan 2023; Mid Flutter Developer, Jan 2023 – Jan 2024; Team Leader, Flutter Team, Jan 2024 – Feb 2025 -
G-Group.dev 2021–2022 : Flutter Developer, Dec 2021 – Mar 2022 -
wtf.city 2021 : Junior Flutter Developer, Jun 2021 – Nov 2021 - Teaching 2020–2024 : Programming trainer, Jul 2020 – Oct 2020; German teacher, Nov 2020 – Jan 2024
- LeanCode : Senior Flutter Engineer, May 2025 – now
- Tide : Mobile Software Engineer (Flutter), Offers & Rewards, Jun 2025 – Jan 2026; Mobile Software Engineer (Flutter), CoSec, Jan 2026 – Jul 2026
- Yanosik S.A. : Junior Flutter Developer, Dec 2021 – Jan 2023; Mid Flutter Developer, Jan 2023 – Jan 2024; Team Leader, Flutter Team, Jan 2024 – Feb 2025
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Leader School Poznań Winogrady : German teacher, Nov 2020 – Jan 2024 - G-Group.dev : Flutter Developer, Dec 2021 – Mar 2022
- wtf.city : Junior Flutter Developer, Jun 2021 – Nov 2021
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UCanCode : Programming trainer, Jul 2020 – Oct 2020
Hover a bar for details, click it to jump to the role. Tap a company to see the details.
- LeanCode
Contract · Remote
May 2025 – now
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Senior Flutter Engineer
May 2025 – now
Building Flutter apps for LeanCode's enterprise clients. I also helped build the app for Flutter Tech Summit, LeanCode's conference.
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- Tide
Contract · Remote
Jun 2025 – Jul 2026
A major international fintech platform for small businesses in the UK, India, France and Germany. More than a hundred Flutter engineers work in a single monorepo.
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Mobile Software Engineer (Flutter)
CoSecJan 2026 – Jul 2026
Owned the Companies House filing flows: address changes, authentication codes, the CS01 confirmation statement and their analytics. Also navigation architecture patterns, Flutter upgrades and internal engineering docs.
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Mobile Software Engineer (Flutter)
Offers & RewardsJun 2025 – Jan 2026
Built and shipped the Rewards Hub, the Marketplace, deep links and monitoring.
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- Yanosik S.A.
Full-time · Poznań
Dec 2021 – Feb 2025
The Polish company behind Yanosik, an app for more than 5 million drivers. Besides Yanosik, I worked on Autoplac, FlotisManager and the dealer apps.
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Team Leader, Flutter Team
Jan 2024 – Feb 2025
Led the Flutter team: sprint planning, well-described tasks, and code quality and architecture standards that I upheld in code review. Built and maintained the internal tools for building and releasing the apps, worked with DevOps, backend and QA on processes, and mentored developers. In the AI team, I built an internal tool and helped roll out AI tools across the company.
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Mid Flutter Developer
Jan 2023 – Jan 2024
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Junior Flutter Developer
Dec 2021 – Jan 2023
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- G-Group.dev
Freelance · Poznań
Dec 2021 – Mar 2022
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Flutter Developer
Dec 2021 – Mar 2022
Smart City Poznań: null-safety migration, production releases and sign-in with ID.Poznań over OpenID Connect.
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- wtf.city
Remote
Jun 2021 – Nov 2021
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Junior Flutter Developer
Jun 2021 – Nov 2021
My first commercial Flutter job: a mobile app built with Flutter, Appwrite and Python.
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Teaching, on the side
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German teacher
Leader School Poznań Winogrady · Nov 2020 – Jan 2024
Taught German to children and adults, online and in person.
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Programming trainer
UCanCode · Jul 2020 – Oct 2020
Taught kids web programming: HTML, CSS, JavaScript, PHP and MySQL.
Recommendations
What colleagues say
Excerpts from recommendations on my LinkedIn profile.
He's a trustworthy, sharp senior engineer who's also just easy to work with. That combination is rarer than it should be. … Even when we disagreed on his PRs, ego never got in the way. He cared more about building a good product than about being right.
What really sets Dawid apart is his out-of-the-box thinking. He never settles for the obvious answer and consistently finds smart, creative solutions to problems that leave others stuck.
He consistently looks beyond immediate tasks to understand overarching business goals, allowing him to identify and suggest impactful product improvements.
About
How I work
I like the unglamorous parts of a codebase: clear module boundaries, code review that teaches something, release tooling nobody has to babysit. As a team leader I set those standards; as an engineer I try to leave every module a little better than I found it.
Teaching came first. Alongside my first engineering jobs I spent three years teaching German to kids and adults, and before that I taught children to build websites. It still shapes how I mentor, review and write docs.
Toolbox
- Flutter & Dart
- Clean Architecture BLoC CQRS add-to-app method channels dart:ffi Flutter Web large monorepos
- Platform
- iOS and Android Kotlin Swift push notifications deep links Mapbox and MapLibre Firebase OpenID Connect
- Shipping
- CI/CD pipelines build and release tooling Crashlytics and monitoring code review
- Team
- Leading a Flutter team mentoring code quality and architecture standards sprint planning rolling out AI tools
- Other
- Python JavaScript Shell SQL Atlassian Forge MCP servers
Languages
I work in three languages
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Cześć!
Polish
Native
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Hallo!
German
Bilingual
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Hello!
English
Full professional
Contact
Let's talk.
Building something with Flutter, or looking for someone to look after a big app? Email is the quickest way to reach me, in English, Polish or German.