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.ResponsibilitiesDesign and develop applications using C# and .NET CoreImplement frontend components using Angular and TypeScriptDesign and optimize SQL Server databasesDevelop and maintain REST-based integrationsCreate and maintain unit and automated E2E testsParticipate in system design and architectural discussionsMaintain high code quality and review standardsCollaborate with Analysts, QA and DevOps teamsSupport continuous improvement of development processesRequired skillsMinimum 5 years of commercial experience in software developmentStrong experience with C#, .NET Core and SOLID principlesExperience with Angular and TypeScriptExperience designing relational databases (SQL Server)Practical experience with Docker and KubernetesExperience with unit testing and automated E2E testsKnowledge of software design and system architecture methodologiesExperience with tools such as Git, Visual Studio, VS Code, Jira, TeamCityKnowledge of PowerShell and BashEnglish level sufficient for technical documentationNative or near-native (C2) proficiency in PolishNice to haveMicrosoft certifications (.NET / ASP.NET / MCTS)Experience with WCF, MVC.NET, ASP.NETEnterprise integration experience (SSIS or similar)Margo Offers:Long-term cooperation on stable banking projectRemote-first work model with regular on-site collaboration daysEmployment or B2B contract (based on your preference)Benefits such as medical care and sports cardOpportunity to grow in enterprise-scale systemsCollaboration with experienced developers and architectsFriendly and supportive MARGO team