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 monthWe are currently looking for a Senior .NET Developer to join a long-term enterprise banking project. You will work on scalable backend and fullstack applications delivered in a modern development environment with strong focus on code quality, automation and stable delivery processes. This role is ideal for an experienced engineer who takes ownership of delivered solutions, actively participates in technical decisions and supports high engineering standards across the team.ResponsibilitiesDesign and develop backend services using C# and .NET Core / .NET FrameworkBuild and extend frontend components using Angular and JavaScriptDesign and maintain REST APIsDevelop scalable enterprise applicationsCreate and maintain automated tests (unit and E2E – Cucumber)Participate in technical and architectural discussionsTake ownership of code quality and code review standardsWork with CI/CD pipelines and deployment automationCollaborate with DevOps, QA, Analysts and Product teamsSupport less experienced developers through technical guidanceMust have (Senior level)Strong commercial experience with C#, .NET Core and .NET FrameworkAdvanced knowledge of Angular and JavaScriptDeep understanding of SOLID principles, design patterns, IoC and DIAdvanced experience with unit testing and automated E2E testing (Cucumber)Strong REST API development skillsExperience working on large-scale enterprise systemsAdvanced experience with Docker and KubernetesKnowledge of CI/CD processesExperience with Jira, Git, TeamCity or JenkinsNative or near-native (C2) proficiency in PolishNice to haveExperience with cloud platforms (Azure, GCP)Ansible or GitHub ActionsPowerShellEnterprise integration experienceMicrosoft certifications (.NET / ASP.NET)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