.NET Developer

Senior • Hybrid

Warsaw, Poland

We are looking for a .NET Developer to join the front-office Trading Tool team that builds and maintains high-performance applications used by traders for market-making. You will work on a complex system combining WPF/DevExpress interfaces, browser-based tools, and integrations with multiple internal APIs. The team operates in a distributed setup between France and Poland.

The role requires working from the Warsaw office two to three days per week.

Your tasks

Design, develop, test, and deploy high-performance trading applications operating in a multi-threaded environment
Build and maintain WPF/DevExpress user interface components used by traders
Translate technical and functional requirements into detailed user stories and collaborate closely with Agile Masters and Business Analysts
Deliver and support applications through Continuous Delivery (DevOps)
Maintain and improve production support tools and participate in non-regression testing
Recommend and implement improvements to application performance, architecture, and development processes
Provide clear and consistent progress updates to traders and stakeholders

Requirements

Minimum 5 years of experience in backend C# development
Strong understanding of multithreaded programming and microservices architecture
Experience with WPF/DevExpress
Fluency in English (spoken and written)
Excellent communication and teamwork skills
Proactive, solution-oriented, and collaborative mindset
Open to a hybrid work model (2-3 days per week on-site)
Fluent in Polish required
Residing in Poland required

Sii

Sii is a company recognized as a "Great Place to Work" since 2015, thanks to employee feedback and the implementation of new ideas. Established in 2006, Sii has demonstrated financial stability with a revenue of 2.1 billion PLN and no debts. The company shares its profits with employees, having allocated over 76 million PLN for this purpose since 2022. Sii offers a rich benefits package, including private healthcare, a cafeteria platform, and discounts on cars. Employees can work in comfortable A-class offices or remotely. Sii is involved in numerous fascinating projects for prestigious global brands and invests 1 million PLN annually to support employee passions and volunteer actions. The company emphasizes personal development through meetups, webinars, a training platform, and a technology blog. Sii is characterized by a fantastic atmosphere created by its "Sii Power People."