Alex Kondratenko
Senior .NET Developer
About me
Upwork Profle

Portfolio

Services

Web Systems & Backend APIs

Web applications and APIs built for performance and growth.

Desktop Applications

High-performance desktop applications for complex business workflows.

System Architecture & Design

Clear, scalable architectures designed for long-term evolution.

Legacy System Modernization

Modernizing existing systems without disrupting business operations.

Long-Term Support & Ownership

Ongoing support and responsibility for systems after delivery.

Business-Critical Software Development

Stable, high-reliability software for core business operations.

My services

Senior .NET Developer with 20+ years of practical experience

I work on software that has to function reliably in the real world — not just look good in a demo.

My main stack includes C#, .NET, WPF, ASP.NET Core, SQL, Office automation, and related technologies. I also have experience with C++, Visual Basic, Delphi, deployment tooling, installer creation, and modernization of older systems.

Over the years I’ve delivered desktop applications, backend components, automation tools, data-processing solutions, and custom software for clients in different domains. I’m strongest in projects that need careful engineering, independent execution, and long-term maintainability.

If you need a developer who can understand an existing system, improve it, and take real ownership of the result, let’s talk.

What clients say

Improved the solution beyond the original specification.
Handled a complex, stop-and-start engagement smoothly, stayed available on short notice, and guided us toward a better technical implementation.

Solved complex technical problems clearly and efficiently.
Professional, experienced, and easy to communicate with — even for a non-technical client. Will definitely return for future work.

Delivered a precise API-to-Excel integration.
Worked closely with our engineer to turn multiple API endpoints into reliable Excel functions under strict requirements.

No-nonsense execution with strong ownership.
Proactive, fast to respond, flexible with billing, and focused on results despite coordination challenges.