Senior .NET Developer (Banking) – Remote (Poland)

Work model: 100% remote (candidates must be based in Poland)
Contract type: B2B
Industry: Banking / Investment Banking

We are looking for an experienced Senior .NET Developer to join a distributed engineering team working on critical banking systems. The role focuses on extending and modernising applications used across securities and banking operations, with a strong emphasis on system design, scalability, and cloud transformation.
You will work end-to-end on business-critical systems, closely collaborating with Business Analysts, without a separate QA team. A solid background in banking or financial services is essential.
Main Responsibilities:
• Design, develop, and extend .NET-based systems supporting multiple banking entities
• Contribute to the integration of securities and core banking platforms
• Support and enhance a portfolio of ~17 applications across product control and risk management
• Work with an in-house development framework in a full-stack capacity
• Participate in scaling applications for cloud-based, containerized environments
• Collaborate closely with business stakeholders to deliver robust solutions
• Ensure high code quality through unit and integration testing
Key Requirements:
• 5+ years of professional experience as a .NET / C# Developer
• Hands-on experience in the banking or investment banking sector (mandatory)
• Full-stack development experience (backend-focused, frontend included)
• Strong understanding and practical application of SOLID design principles
• Experience with document-based databases (e.g. MongoDB)
• Experience with event-driven / event-based messaging frameworks
• Solid knowledge of unit and integration testing
• Experience working end-to-end on applications (development, testing, support)
• Ability to work independently in a fast-paced, regulated environment
• Availability during UK business hours
Nice to Have:
• Experience with cloud platforms and application migration to cloud
• Experience with container technologies (e.g. Docker, Kubernetes)
• Exposure to systems such as Murex or large in-house banking platforms
• Background in securities, risk, or product control systems
Other Details:
This role is 100% remote with candidates required to be located in Poland. The contract is on a B2B basis within the banking and investment banking industry.