Fullstack .Net Engineer

We are looking for FullStack Engineer (.NET & React) Location: Kraków / Hybrid (7 days in the office per month)Contract Type: B2B Contract Seniority: Mid / Senior     About the Project Join a high-impact modernization initiative for a leading player in the banking sector. We are transforming a portfolio of approximately a dozen .NET applications and MSSQL databases into a modular, cloud-native Azure architecture. As a FullStack Engineer, you will play a dual role: evolving existing production services (including legacy UI and desktop components) while systematically extracting business logic to re-implement it into a modern, scalable ecosystem. This is a unique opportunity to influence the transition from monolithic architectures to high-performance, distributed cloud services.   Your Responsibilities • Design & Development: Build backend services and APIs using .NET 6/8 following Clean Architecture and DDD patterns. • Frontend Evolution: Develop and maintain React + TypeScript frontends, managing the incremental migration from legacy UI modules. • Modernization: Read, refactor, and extract complex business logic from legacy .NET codebases and T-SQL stored procedures. • Quality Assurance: Write and maintain comprehensive automated tests (Unit, Integration, Contract, and E2E). • DevOps & Observability: Create CI/CD pipelines (Azure DevOps/GitHub Actions) and instrument services for deep observability (metrics, logs, distributed traces). • Collaboration: Participate in domain modeling, architecture discussions, and Agile ceremonies with Architects and Product Owners.   Skills & Experience We Require • Experience: 5+ years of commercial experience with C# and the .NET ecosystem (both Framework and .NET Core/6+). • Database Expertise: Strong proficiency in EF Core and MSSQL (including query tuning, transactions, and indexing). • Frontend: Solid production experience with React and TypeScript. • Web Services: Practical experience in building and securing REST APIs (Auth, Versioning, Validation). • Cloud: Familiarity with Azure services (App Service, Functions, SQL, Service Bus, Storage). • Testing & Tooling: Experience with xUnit, Jest, and Playwright/Cypress, as well as disciplined Git practices. • Legacy Handling: The ability to read and reason about legacy codebases (ASP.NET MVC, Razor, WPF, or WinForms). • Communication: English at a B2+ level for technical documentation and team collaboration.   Nice to Have • Experience with Infrastructure as Code (Terraform or Bicep). • Knowledge of Docker and Kubernetes (AKS). • Background in migrating monoliths to microservices. • Azure Developer Associate certification.   What We Offer • Impact: Real influence on the architecture and the cloud migration roadmap. • Autonomy: Direct collaboration with Tech Leads and Architects in a flat structure. • Modern Stack: Opportunity to work with the latest .NET versions (6/8) and React. • Efficiency: Fast technical onboarding with immediate access to repos, CI/CD pipelines, and monitoring tools. • Flexible Hybrid Model: Remote-first approach with only 7 planned days in the Kraków office per month. • Benefits : Luxmed and Multisport Card