Senior Backend Software Engineer (.NET)

About the Position

We are seeking an experienced Senior Backend Software Engineer (.NET) to join our team in Krakow, Poland. The role involves designing, building, and operating backend services within a modern, scalable microservices environment. You will work with ASP.NET Core, Azure Functions, SQL Server, and Azure CosmosDB to deliver high-performance, secure solutions for cloud and hybrid environments.

Responsibilities

• End-to-end development of backend features using ASP.NET Core APIs, Azure Functions, SQL Server, and CosmosDB
• Building and extending.NET services in a microservices architecture
• Implementing resilient, asynchronous workflows using Azure Service Bus
• Designing secure and efficient data access patterns (SQL Server, CosmosDB)
• Ensuring multi-tenant data isolation and compliance with security standards
• Using Azure services such as Service Bus, Blob Storage, App Configuration, Application Insights, and Entra ID
• Writing unit and integration tests (xUnit, Moq, FluentAssertions)
• Contributing to CI/CD pipelines (GitHub Actions, Azure DevOps)
• Working with Terraform, Docker Compose, and Azurite
• Identifying and resolving performance, security, and reliability issues
• Independently delivering backend features from design to production
• Participating in architecture discussions and code reviews
• Collaborating with product and frontend teams on API design
• Mentoring junior engineers and promoting AI-driven development practices

Requirements

• Minimum 5 years of experience in backend or distributed systems engineering
• Strong proficiency in C# /.NET 8/10, ASP.NET Core, Azure Functions
• Experience with SQL Server (T-SQL, EF Core, RLS) and NoSQL databases (CosmosDB preferred)
• Practical knowledge of Azure services (Functions, Service Bus, Blob Storage, App Configuration, App Insights)
• Understanding of OAuth2, JWT, and identity provider integrations
• Experience with multi-tenant SaaS architectures
• Familiarity with asynchronous, message-driven systems
• Knowledge of CI/CD, Terraform, Docker/Kubernetes
• Strong testing discipline and communication skills

We Offer

• Health benefits & insurance
• Multisport card
• Learning and development opportunities
• Flexible work schedule
• Innovative work in cybersecurity and AI-native environment
• Opportunities for career growth

About the Company

Grafton Recruitment is an international recruitment and staffing agency specializing in talent acquisition and workforce solutions across a wide range of industries. The company partners with local and global organizations to support their growth by identifying and placing qualified professionals in key roles. With operations in multiple countries, Grafton Recruitment focuses on delivering high-quality, client-oriented services, emphasizing professionalism, market expertise, and long-term relationships with both clients and candidates.

Apply now!