Sergei K.Private profile: Upwork shows its earnings only to signed-in members, so we check it every few weeks, not daily. MRR here is a rough estimate (Upwork's six-month earnings ÷ months active). Last read Nov 5, 2026.

enior C# / .NET developer with 20+ years of experience building Windows desktop software, integrating with third-party systems and keeping legacy .NET applications running. Top Rated with 100% Job Success. What I can help you with: - WPF and WinForms applications: new development, refactoring, performance and multi-threading issues - Integrations with third-party Windows software, including apps with no API: UI Automation, FlaUI, Win32, direct database access - Medical imaging: DICOM and common image formats (JPG, PNG, BMP, TIFF), integration with dental imaging systems - REST API clients and ASP.NET / ASP.NET Core backends with Entity Framework, SQL Server or MySQL - Installers and updates: MSI (Advanced Installer, WiX), silent auto-update, Windows services - Maintenance and modernization of legacy .NET Framework applications, including migration to modern .NET - Visual Studio extensions (VSPackage); MS Dynamics CRM customization and data migration Recent experience: - Denti.AI (2020–2026): built the Windows clients that bring AI X-ray analysis and voice-driven periodontal charting into dental software such as Dentrix, Open Dental, Eaglesoft, ClearDent, Carestream and Dexis. REST APIs, DICOM images, real-time audio streaming with failover and automatic reconnection, and production support on live clinic machines. - Dimodelo (2013–2020): a Visual Studio extension for data warehouse design, with a code generation engine producing SQL Server and Azure SQL schemas and ETL code. - Earlier: MS Dynamics CRM 2011 migration with custom Silverlight UI, commercial .NET libraries for the Excel and Word binary formats. - Personal project: Strategium, a multiplayer strategy game with an ASP.NET Core server, MySQL and an Android (Java) client. Technologies: C#, .NET Framework / .NET, ASP.NET Core, ASP.NET MVC, WPF, WinForms, MVVM, WebView2, multi-threading, async/await, REST APIs, UI Automation, FlaUI, Win32 API, ADO.NET, Entity Framework, XML/XSLT, XML web services, encryption, DICOM, MS SQL Server, MySQL, SQLite, MSI, WiX, Advanced Installer, Git. Also: GTK# on Windows and macOS, JavaScript and jQuery, Android (Java), Scribe, Azure and Amazon S3. Older experience with C++, Delphi, COM, OpenGL and DirectX, which helps when a legacy system needs care. How I work: I give honest estimates, flag risks early and keep you updated without being asked. I'm comfortable owning a task end to end, from design to installer to troubleshooting on the customer's machine. Based in Batumi, Georgia (UTC+4). If your project involves Windows desktop software, integrations, medical imaging or an aging .NET codebase, send me a short description. I'll reply with questions and a realistic plan.