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

Work model: 100% remote (candidates must be based in Poland)Contract type: B2BIndustry: Banking / Investment BankingWe 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 entitiesContribute to the integration of securities and core banking platformsSupport and enhance a portfolio of ~17 applications across product control and risk managementWork with an in-house development framework in a full-stack capacityParticipate in scaling applications for cloud-based, containerized environmentsCollaborate closely with business stakeholders to deliver robust solutionsEnsure high code quality through unit and integration testingKey Requirements:5+ years of professional experience as a .NET / C# DeveloperHands-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 principlesExperience with document-based databases (e.g. MongoDB)Experience with event-driven / event-based messaging frameworksSolid knowledge of unit and integration testingExperience working end-to-end on applications (development, testing, support)Ability to work independently in a fast-paced, regulated environmentAvailability during UK business hoursNice to Have:Experience with cloud platforms and application migration to cloudExperience with container technologies (e.g. Docker, Kubernetes)Exposure to systems such as Murex or large in-house banking platformsBackground in securities, risk, or product control systemsOther 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.