Senior Full-Stack Engineer (.NET / React / Azure / Terraform)

About the role

We are looking for a Senior Full-Stack Engineer to join a large-scale modernization programme focused on migrating a portfolio of legacy applications and databases to a modular, cloud-native architecture on Microsoft Azure. You will work across backend, frontend, database and cloud/DevOps areas, contributing directly to production solutions and supporting the incremental transformation of business-critical systems.

Your responsibilities

• Design and implement backend services and REST APIs in .NET 9 using Clean Architecture.
• Build and maintain React and TypeScript microfrontends integrated through module federation.
• Develop and optimize MSSQL and Azure SQL schemas, stored procedures, views and EF Core queries.
• Create and maintain Terraform code for provisioning Azure resources across environments.
• Build, optimize and support Azure DevOps CI/CD pipelines using YAML.
• Integrate Entra ID / MSAL authentication and apply security best practices, including Key Vault and least-privilege access.
• Implement observability with Application Insights, structured logging, health checks and alerting.
• Refactor legacy .NET and T-SQL solutions and extract business logic during migration.
• Create and maintain unit, integration, API and end-to-end automated tests.
• Troubleshoot production incidents, deliver fixes and support deployments.
• Collaborate in Agile ceremonies, estimate work, define acceptance criteria and participate in code reviews.

Required skills and experience

• At least 5 years of commercial full-stack development experience with C# and .NET, including .NET 6+ and ASP.NET Core.
• Strong knowledge of EF Core and MSSQL / Azure SQL, including query tuning, indexing, transactions and stored procedures.
• Hands-on experience with Azure services such as App Service, Azure SQL, Storage, Key Vault, Functions and Service Bus.
• Practical experience with Infrastructure as Code using Terraform, including modules, state management and multi-environment provisioning.
• Experience with Azure DevOps CI/CD and YAML pipelines.
• Experience building and securing REST APIs, including validation, versioning, OAuth, JWT and Entra ID.
• Experience with automated testing tools such as xUnit, Jest, Vitest or Playwright.
• Knowledge of Application Insights, OpenTelemetry and structured logging.
• Good Git practices and code review discipline.
• English at B2 level or higher for technical communication.

Nice to have

• Production experience with React and TypeScript.
• Experience with Azure Data Factory, Databricks, Spark, Power BI or SSRS.
• Knowledge of microfrontends and module federation.
• Experience with Docker and Kubernetes / AKS.
• Knowledge of Bicep or ARM templates.
• Experience with event-driven integration using Service Bus or Event Hubs.
• Experience modernizing legacy technologies such as ASP.NET MVC, Razor, WPF, WinForms, Windows Services or SSIS.
• Azure certifications such as AZ-204, AZ-400 or AZ-104, or HashiCorp Terraform Associate.

What we offer

• Hybrid work in Kraków, with 6 days per month in the office.
• B2B contract
• Rate : 160 -185 PLN netto/hour
• Benefits: Luxmed, Multisport Card