Jacek Janur
Mobile Developer
I build reliable mobile products from idea to production - combining product thinking, thoughtful interfaces and code that stays maintainable after launch.
Flutter · Kotlin · React Native · Backend
About
Over 4+ years I've worked across the full product lifecycle: gathering requirements, designing interfaces, building mobile apps and APIs, shipping to stores and learning from real users. My approach is shaped by zanshin - staying focused not only while building, but after the product reaches the real world.
Featured work
Trawell
A location-based city game that turns exploring local landmarks into interactive challenges. I co-founded the product and helped take it from concept to the App Store and Google Play.
- Built: UI/UX, Flutter app and Django REST API.
- Owned: product discovery, releases and user feedback.
- Result: 2,000+ downloads, 22+ reviews and a 4.6/5 rating.
Hanafuda
An online Koi-Koi game I created so friends could play Hanafuda together. I designed and built the complete product, from game rules to deployment.
- Built: React frontend, Rails backend and complete game logic.
- Solved: turn flow, scoring and consistent multiplayer state.
- Scope: independent end-to-end product and deployment.
⚠ API runs on a free tier, may take a moment to wake up on first load.
Experience
Building native Android apps and maintaining React Native codebases. Working directly with clients - from Bluetooth integration to bug tracking, start to finish.
Co-founded Trawell. Designed the UI/UX, built the backend API, and learned that listening to users matters as much as writing good code. 2,000+ downloads, 4.6/5 rating.
Mobile and desktop apps in Flutter. Payment systems, booking features, rapid MVP development - seeing different approaches work (and fail) in the real world.
Skills
Let's work together
Have a mobile product to build or improve? Tell me what you're working on and where you need support.