Senior FullStack Engineer (.NET / Azure / React)

We are seeking a highly skilled Senior FullStack Engineer with expertise in .NET, Azure, and React. The successful candidate will join our team in evolving our portfolio of .NET applications and MSSQL databases to a modular, cloud-native architecture while enhancing legacy systems.What we offer: Long Term Cooperation Rate: 160-180 pln/h + VATB2B Contract 5 days per month in office KrakowMain Responsibilities:Lead architecture decisions and migration strategies.Create and maintain architectural decision records (ADRs) and API guidelines.Implement hands-on coding and conduct code reviews for core services.Mentor team engineers and formalize best practices.Design CI/CD automation solutions and self-service tooling.Ensure system reliability through observability and pattern implementation.Oversee data integrations and SQL Server performance strategies.Manage technical risks and prioritize technical debt.Collaborate with stakeholders to shape the development roadmap.Key Requirements:8+ years of commercial experience in Senior/Tech Lead/Full-Stack roles.Expertise in C#/.NET, with solid backend design skills.Proven Azure architecture experience.Advanced SQL Server skills including performance tuning.Strong React and good Angular experience.Experience with modernizing legacy UIs.Understanding of ETL processes and reporting tools.CI/CD and automation practice proficiency.English proficiency (B2/C1 level) for communication and documentation.Nice to Have:Operational experience with Kubernetes (AKS).Advanced use of Terraform.Familiarity with Databricks and Spark SQL.Experience with event streaming technologies.Performance tooling and chaos engineering experience.Understanding of security best practices in software design.Other Details: This is a contract position with a hybrid work model (5 days in the office per month) based in Kraków. Working hours are from 09:00 to 17:00 CET.