Senior .NET Developer — Cloud-Native Modernization (Azure)

Sii Poland; Kraków; Hybrid; PLN 180,000 - 240,000; Full time

Benefits offered by this job

Great Place to Work

Centre of internal trainings

Profit sharing

Medical care

Open management team

Trips and integration events

MySii app

Flexible work hours

Job summary

Sii Poland is seeking a versatile Senior .NET Developer to join a modernization program in Kraków. You will migrate legacy applications to a cloud-native Azure architecture, building .NET APIs, React microfrontends, and Azure services in a hybrid work setting.

Responsibilities include backend and frontend development, database tuning, IaC with Terraform, CI/CD in Azure DevOps, and implementing secure authentication with Azure AD. Strong English communications are required.

Qualifications

• Minimum 5 years of commercial full-stack .NET experience (C#, ASP.NET Core).
• Strong EF Core and MSSQL/Azure SQL with query tuning skills.
• Hands-on Azure (App Service, SQL, Functions) and Terraform IaC.
• Experience with Azure DevOps YAML pipelines and CI/CD workflows.
• Proficient in building secure REST APIs and modern frontend with React/TypeScript.
• Experience in automated tests (xUnit/Jest) and observability tools.

Responsibilities

• Design and implement backend services and REST APIs in .NET 9 using Clean Architecture.
• Develop React + TypeScript microfrontends and integrate with APIs.
• Evolve MSSQL / Azure SQL schemas and performance tuning.
• Author/maintain Terraform IaC for Azure resources.
• Build and optimize CI/CD pipelines in Azure DevOps.
• Implement Azure AD auth and security best practices.
• Instrument services for observability and health checks.
• Refactor legacy .NET/T-SQL during migration.
• Write/maintain automated tests (unit, integration, E2E).
• Troubleshoot production incidents and support deployments.

Skills

C# / .NET

ASP.NET Core

EF Core

Azure

React

TypeScript

MSSQL / Azure SQL

Terraform

Azure DevOps

REST APIs

CI/CD pipelines

xUnit / Jest

Observability

Git

Tools

Azure DevOps

Terraform

Jest

Kubernetes

Job description

Sii Poland is seeking a versatile Senior .NET Developer to join a modernization program in Kraków. You will migrate legacy applications to a cloud-native Azure architecture, building .NET APIs, React microfrontends, and Azure services in a hybrid work setting.

Responsibilities include backend and frontend development, database tuning, IaC with Terraform, CI/CD in Azure DevOps, and implementing secure authentication with Azure AD. Strong English communications are required.