Back-End Developer (.NET / C#)

Location: Poland (approx. 90% remote, occasional on-site visits in Warsaw)Start Date: ASAPAbout the RoleWe are looking for experienced Back-End Developers to join a long-term software development project. You will be responsible for designing, developing, and maintaining backend applications, building APIs, optimizing databases, and ensuring high-quality software delivery within an Agile environment.ResponsibilitiesDesign and develop software based on technical requirementsBuild and maintain REST APIsDesign, develop, and optimize relational databasesDebug, test, and improve application performanceCreate unit and integration testsCollaborate with cross-functional teams in an Agile/Scrum environmentReport progress and contribute to technical documentationRequirementsHigher education degreeMinimum 5 years of professional experience in IT projectsAt least 3 years of experience as a Back-End Developer within the last 5 yearsStrong knowledge of C# and .NET CoreExperience developing web and desktop applicationsPractical experience designing and implementing REST APIsGood understanding of Clean Architecture and Domain-Driven Design (DDD)Strong knowledge of MS SQL and/or PostgreSQLExperience with SQL optimization, indexing, and stored proceduresHands-on experience with Entity Framework Core and DapperKnowledge of authentication, authorization, and encryption mechanisms (JWT, OAuth2, FIDO2)Experience writing unit and integration testsFamiliarity with Azure DevOps and GitExperience working in Agile/Scrum teamsEnglish at a level allowing you to work with technical documentationWhat We OfferB2B contract via ExperisPrivate healthcare (Medicover)Multisport cardGroup life insuranceFlexible work model with approximately 90% remote workLong-term project with modern .NET technologiesOpportunity to work in an experienced and collaborative development team