Workplace type: Remote-first (with on-site team meetings twice a month in Warsaw)Contract type: B2B / Permanent (UoP)Salary (B2B): 120 – 135 PLN + VAT / hourAvailability: ASAP/ up to 1 month About the role  We are looking for a Senior .NET Developer to join long-term enterprise IT projects delivered in the banking environment. You will work on complex business applications, cooperating closely with analysts, QA engineers and product stakeholders.This role is designed for experienced developers (5+ years) who are comfortable working in structured enterprise environments and value clean code, testing and high engineering standards.Responsibilities Design and develop applications using C# and .NET Core Implement frontend components using Angular and TypeScript Design and optimize SQL Server databases Develop and maintain REST-based integrations Create and maintain unit and automated E2E tests Participate in system design and architectural discussions Maintain high code quality and review standards Collaborate with Analysts, QA and DevOps teams Support continuous improvement of development processes Required skills Minimum 5 years of commercial experience in software development Strong experience with C#, .NET Core and SOLID principles Experience with Angular and TypeScript Experience designing relational databases (SQL Server) Practical experience with Docker and Kubernetes Experience with unit testing and automated E2E tests Knowledge of software design and system architecture methodologies Experience with tools such as Git, Visual Studio, VS Code, Jira, TeamCity Knowledge of PowerShell and Bash English level sufficient for technical documentation Native or near-native (C2) proficiency in Polish Nice to have Microsoft certifications (.NET / ASP.NET / MCTS) Experience with WCF, MVC.NET, ASP.NET Enterprise integration experience (SSIS or similar) Margo Offers: Long-term cooperation on stable banking project Remote-first work model with regular on-site collaboration days Employment or B2B contract (based on your preference) Benefits such as medical care and sports card Opportunity to grow in enterprise-scale systems Collaboration with experienced developers and architects Friendly and supportive MARGO team