Denis User

Founded and scaled a boutique IT agency delivering B2B mobile and hybrid apps; drove client acquisition, led cross-functional teams (3–8), and improved on-time delivery to 95% while accelerating initial project delivery by ~30%.

Led development of key streaming features (offline listening, infinite playback) increasing user engagement by ~15% and managed transition to a freemium model for 100,000+ users while improving feature adoption via A/B testing.

Engineered advertising and security Android SDKs embedded in 10+ apps producing 5M+ monthly ad impressions; halved SDK release prep time by implementing CI/CD and Maven publishing.

Developed AOSP-based POS applications deployed on 600,000+ devices and led migrations (Android 6→10, RxJava upgrades), reducing malfunction rates by 15% via a GMP-compliant master app and modernization efforts.

Designed a modular single-activity MVVM architecture to enable an MVP in 5 months and improved UI responsiveness by 15% using reactive RxJava implementations for an Uber-like truck service.

Sole Android developer on a two-person team delivering a secure cryptocurrency wallet (Pranacoin) to Google Play; implemented MVVM, QR-based transactions and local persistence, eliminating critical post-launch bugs.

Completed a Specialist's degree in Biophysics with coursework and training in biophysical methods and analysis from 1998 to 2002.