FullStack Engineer

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 principles Build and maintain React TypeScript frontends, gradually migrating legacy UIs Read, refactor, and extract business logic from legacy .NET and TSQL codebases Write and maintain extensive automated tests across unit, integration, contract, and E2E layers Create and manage CI/CD pipelines using Azure DevOps or GitHub Actions and Infrastructure as Code artifacts Instrument services for observability through metrics, logs, and distributed tracing Troubleshoot production incidents and deliver timely fixes and support deployments Participate in architecture and domain modeling activities with DDD patterns and bounded contexts Collaborate in Agile ceremonies, estimate tasks, and define acceptance criteria You'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 environments Hands-on experience building and securing REST APIs with validation, versioning, and authentication Familiarity with Azure services such as App Service, Functions, Azure SQL, Storage, and Service Bus Experience with CI/CD and automated testing tools like xUnit, Jest, Playwright, or Cypress Knowledge of observability tools like Application Insights or OpenTelemetry Ability to interpret and work with legacy codebases ( ASP.NET MVC, Razor, WPF, WinForms) Good Git practices and thorough code review discipline Fluent Polish and English language skills (B2) for effective technical communication It is a strong plus if you have: Infrastructure as Code experience with Terraform or Bicep Docker and Kubernetes (AKS) expertise Playwright codegen or Cypress E2E automation experience Experience migrating monoliths to microservices architecture Deep understanding of SQL Server internals and performance profiling Azure certifications such as Azure Developer Associate Eligibility 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 conditions Enhance your skills and develop your expertise in the financial industry Work on the most strategic projects available in the market Define your career roadmap and develop yourself in the best and fastest possible way by delivering strategic projects for different clients of ITDS over several years Participation in Social Events, training, and work in an international environment Access to an attractive Medical Package Access to Multisport Program GETREADY Internal job ID 8095 You can report violations in accordance with ITDS's Whistleblower Procedure available here .