Unleash innovation at scale — revolutionize legacy systems into cloud-native solutions!Kraków-based opportunity with hybrid work model (5 days/monthremote).As a Mid/Senior FullStack Engineer – .NET & React with Azure Experience, you will be working for our client, a leading financial institution, on a transformative project to modernize a portfolio of .NET applications and MSSQL databases into a modular, cloud-native Azure architecture. This initiative aims to reduce technical debt, enhance security, streamline data flows, and enable incremental delivery of services—while supporting legacy UIs and functionalities. You will be instrumental in extracting and reimplementing embedded business logic, boosting observability, and delivering high-quality, scalable software solutions aligned with business and technical goals.Your main responsibilities:Design and implement backend services and APIs in .NET 6/8 utilizing clean architecture principlesBuild and maintain React + TypeScript frontends, gradually migrating legacy UIsRead, refactor, and extract business logic from legacy .NET and TSQL codebasesWrite and maintain extensive automated tests across unit, integration, contract, and E2E layersCreate and manage CI/CD pipelines using Azure DevOps or GitHub Actions and Infrastructure as Code artifactsInstrument services for observability through metrics, logs, and distributed tracingTroubleshoot production incidents and deliver timely fixes and support deploymentsParticipate in architecture and domain modeling activities with DDD patterns and bounded contextsCollaborate in Agile ceremonies, estimate tasks, and define acceptance criteriaYou're ideal for this role if you have:5+ years of commercial experience with C# and .NET (Framework + .NET Core / 6+)Strong expertise in EF Core and MSSQL (query tuning, transactions, indexing)Proven experience with React and TypeScript in production environmentsHands-on experience building and securing REST APIs with validation, versioning, and authenticationFamiliarity with Azure services such as App Service, Functions, Azure SQL, Storage, and Service BusExperience with CI/CD and automated testing tools like xUnit, Jest, Playwright, or CypressKnowledge of observability tools like Application Insights or OpenTelemetryAbility to interpret and work with legacy codebases (ASP.NET MVC, Razor, WPF, WinForms)Good Git practices and thorough code review disciplineFluent Polish and English language skills (B2+) for effective technical communicationIt is a strong plus if you have:Infrastructure as Code experience with Terraform or BicepDocker and Kubernetes (AKS) expertisePlaywright codegen or Cypress E2E automation experienceExperience migrating monoliths to microservices architectureDeep understanding of SQL Server internals and performance profilingAzure certifications such as Azure Developer AssociateEligibility for the role: Only candidates with an existing legal right to work in Europe will be considered for this role.We offer you:ITDS Business Consultants is involved in many various, innovative and professional IT projects for international companies in the financial industry in Europe. We offer an environment for professional, ambitious and driven people. The offer includes:Stable and long-term cooperation with very good conditionsEnhance your skills and develop your expertise in the financial industryWork on the most strategic projects available in the marketDefine your career roadmap and develop yourself in the best and fastest possible way by delivering strategic projects for different clients of ITDS over several yearsParticipation in Social Events, training, and work in an international environmentAccess to an attractive Medical PackageAccess to Multisport Program#GETREADYInternal job ID #8095You can report violations in accordance with ITDS’s Whistleblower Procedure available here.