Oleksandr S.

Mobile App Developer | Flutter | IOS | Android | MVP | Cross-Platfrom

I'm a Flutter Developer with 8+ years of cross - platform mobile experience. Top Rated Plus, $200K+ earned on Upwork, 100% Job Success, ~7,900 hours logged. My contracts typically run 2+ years - I embed with the team and stay for the long haul. I've shipped across healthcare, fitness and wellness, fintech, education, and gaming. My core is Flutter and Dart (6 years), built on an earlier foundation in Xamarin and Unity, so I'm comfortable across the full mobile stack - iOS, Android, and tablets - whether I'm starting from scratch or taking over a codebase that needs rescuing. The project I'm proudest of: migrating a live enterprise app from Xamarin to Flutter in place, without a new store listing, while still shipping features and fixes on it in parallel. I naturally ended up leading that project as it went on, which is where most of my team - lead experience comes from. Across other projects, I've also worked on: - Offline-first apps - Subscriptions and ad monetization - QR code features - Backend implementation via Firebase - I owned the entire backend myself with no dedicated backend developer on the team - App performance optimization - Complex animations, including Lottie and Rive - Mobile games built in vanilla Flutter - Requirements definition and MVP delivery - App Store and Google Play releases - Pixel - perfect UI implementation On the technical side, I work with: - Languages & Frameworks: Flutter & Dart, Xamarin (C#/.NET), Unity (C#) - Architecture: Clean Architecture, SOLID, BLoC/Cubit, Provider, MVVM - Backend: Firebase - Cloud Functions, Firestore, Storage, Auth - Monetization & growth: RevenueCat subscriptions, Google AdMob, deep links - Monitoring: Sentry, Firebase Crashlytics, Analytics, Performance, Sematext - CI/CD: Azure DevOps, Bitrise, Unity Cloud Build, GitHub Actions - Low-code: FlutterFlow, including a Flutter Web project I also work AI - augmented day to day - Claude Code, Cursor, and GitHub Copilot are part of how I actually build, not just buzzwords on a profile. I keep project context files for AI tools, use AI to stress - test requirements before writing code and to generate tests alongside implementation, and it genuinely speeds up the parts of the work that benefit from it. Beyond the code, I've conducted 20+ technical interviews for Flutter roles and mentored other developers. If you need a developer who'll own the outcome and stick around for the long haul, I'd be glad to hop on a short call to talk through your project.