Oleksii K.

Your application can get successful and raise up to 1M users and more. Yoy will never get into endless development. You'll get clear communication, professional support and constant collaboration. Responsibility, creativity, thinking over the code to whole project and making things done. I’m Olex, your full stack developer with 12+ years of programming experience and 8+ of in full stack development experience. I always think about my clients needs first and always share my ideas or doubts about a project I make. I'm honest and fair. I'm confident and I'm actively using AI in my work that helps me to fasten my work up to 20%. Why Choose Me as Your Full Stack Developer? ✅ 8+ years of mobile + back-end development experience ✅ 30+ created full stack systems ✅ 50+ succesfully finished projects on Upwork ✅ 20+ 5-star ratings and glowing client reviews on Upwork ✅ 10+ returning clients ✅ Ranked among the top 10% of Mobile App Developers ✅ End-to-end support from concept to release ✅ AI-powered full stack developer: applications that invokes LLM API integration to provide intelligent, interactive, and context-aware mobile solutions What my client say ⭐️ Oleksii demonstrated himself as a true professional: his deep knowledge and expertise were evident in every response. He not only thoroughly analyzed all aspects of the project but also suggested many valuable ideas I hadn’t even considered. ⭐️ Alex is great. Approaches all tasks by looking at the big picture and working through details with intelligence. Alex helped is get three Apps to production on both iOS and Google Play. Couldn't have done this without him. ⭐️ I’m delighted to share my enthusiasm for working with Alex. From the very beginning of our collaboration, he has demonstrated himself as a professional with a high level of responsibility. Communication with him was extremely comfortable: Alex was always available to discuss issues and responded promptly to messages. ⭐️ Oleksii has it all - incredible work, a strong conviction, incredibly insightful and communicative to problem solving. Could not recommend him more ⭐️ Excellent communication skills. The task was completed on time. My Tech Stack as Full Stack Developer: • Mobile App Languages: Swift, SwiftUI, Objective-C, Kotlin, Java, Flutter, React Native • Web App Applications (RWA): React • Back-end & Web Languages: Javascript, Python, PHP • Back-end integration: Node.js, FastAPI, Lavarel, Firebase, AWS, Supabase • Integrations: APIs, Payment Gateways, Push Notifications, In-app purchases, BLE devices • Approach: Agile Development CI/CD • A Full-stack & Mobile App Developer with deep understanding of mobile ecosystems and experience Core Expertise as a Full Stack Developer: • iOS & Android Mobile App Developer • React web developer • Back-end Node.js, Lavarel & FastAPI Developer • Streaming & Media – real-time video & audio • AI - integrating modern AI APIs, prompt engineering What You Get Working With a Dedicated Mobile App Developer: ✅ Native or Cross-platform apps optimized for speed, stability, and scalability ✅ Web RWA appls optimized for speed, stability, and scalability ✅ Expert-level integrations with IoT, APIs, sensors, and wearables ✅ Clear, consistent communication and progress tracking ✅ Back end implemented by specific case or task with high-load optimisation ✅ Solutions that count in and reduce to zero security risks ✅ Architecture designed for future growth and long-term success 🙌 Let’s talk about your project more deeply and crack the rock together. Click "Invite to Job" or "Hire Now" to start making great smooth and successfull applications!