.NET WinForms Developer

We are looking for an experienced .NET WinForms Developer to join the frontend engineering team and help build high-performance, real-time trading applications used by professional traders.

This role is not about configuring UI frameworks - it is about crafting fast, responsive, custom-rendered desktop UI.

In short

• 100% remote or from the office (Wrocław, Bielsko-Biała) - You choose!
• 125 - 140 PLN/h
• B2B contract
• >5 years of commercial programming experience

Your Daily Missions

• Design, implement and optimize custom WinForms controls (charts, grids, interactive visualization components).
• Work with continuous real-time data streams and ensure ultra-responsive UI under load.
• Ensure smooth multi-threaded UI updates without blocking or freezing.
• Collaborate with backend engineers (C++ systems) to maintain low-latency TCP/socket communication.
• Profile, debug, and tune rendering performance (GC pressure, paint cost, batching, flicker control).
• Improve engineering practices, and influence UI architecture and usability.

The Essentials We're Seeking

• 5+ years of hands-on experience developing desktop applications in C#/.NET (preferably .NET 8).
• Strong expertise in Windows Forms.
• Proven experience building custom UI controls from scratch (inheriting from base controls and implementing custom rendering - not configuring DevExpress/Telerik/Infragistics).
• Experience working with continuous real-time data streams, where data is pushed to the UI (not periodic refresh).
• Strong understanding of multi-threaded UI applications (updating UI safely from worker threads, avoiding freezes and stalls).
• Practical experience in UI performance optimization (reducing redraw cost, minimizing GC pressure, batching updates, preventing flicker).
• Experience working with TCP / socket-based communication.
• Ability to clearly explain previous UI design decisions, trade-offs, and the impact on end users.
• Fluency in English (minimum B2+).

Nice to Have

• Experience with trading systems, market data, or real-time financial applications.
• Familiarity with C++ or interoperability between C# and native components.
• Understanding of high-performance visualization and data interaction patterns.