Vadim K.

$300k+ earned on Upwork • 50+ successful projects • 11,000+ logged hours I specialize in taking over existing mobile projects and helping teams ship reliable products. My strength is quickly understanding complex codebases, solving difficult production issues, improving architecture, optimizing performance, and preparing applications for successful App Store and Google Play releases. I contribute effectively as an individual developer, Tech Lead, or part of an existing engineering team. I have over 20 years of software development experience, including 10+ years building native iOS and Android applications and 7+ years developing cross-platform apps with Flutter and React Native. My experience includes startups, enterprise products, and large-scale mobile platforms serving hundreds of thousands to over one million users. I've worked on marketplaces, social networks, fintech products, delivery platforms, education systems, location-based applications, messaging platforms, and AI-powered mobile solutions. What I can help with • Flutter development (iOS & Android) • React Native development • Native iOS (Swift, SwiftUI, Objective-C) • Native Android (Kotlin, Java) • Backend development (Node.js, NestJS) • Firebase (Authentication, Firestore, Cloud Functions, Storage, FCM) • REST APIs, WebSockets, WebRTC • Architecture improvements • Performance optimization • Production bug fixing • Code refactoring • Technical audits & code reviews • App Store & Google Play releases • Team leadership & mentoring AI & Computer Vision I also build AI-powered mobile features and backend-connected AI workflows, including: • OpenCV • YOLO-based object detection • Image processing pipelines • AI-assisted mobile features • Backend AI integrations • Modern LLM integrations Technologies Flutter • React Native • Dart • Swift • SwiftUI • Objective-C • Kotlin • Java • Node.js • NestJS • Firebase • Firestore • PostgreSQL • REST APIs • WebSockets • WebRTC • OpenCV • YOLO • Clean Architecture • MVVM • MVP • SOLID Why clients work with me ✔ Fast onboarding into existing projects ✔ Strong experience with large production codebases ✔ Architecture improvements instead of temporary fixes ✔ Production-first mindset ✔ Clear communication and transparent progress ✔ Reliable delivery and predictable execution ✔ Comfortable working independently or leading engineering efforts If your project needs an experienced engineer who can quickly understand an existing codebase, solve complex technical challenges, and help deliver a stable, production-ready application, I'd be happy to discuss how I can help.