Working mode: Hybrid (5 days per month at the office in Cracow)Contract type: B2BStart date: January/ beginning of FebruarySummary: The role of Senior FullStack Engineer focuses on transitioning a portfolio of legacy .NET applications to a cloud-native Azure architecture while maintaining and enhancing existing UIs.Responsibilities: Lead architecture, define boundaries, and drive modularization strategies. Create and maintain guidelines for API/versioning and contract standards. Implement and review core services and React frontends. Mentor engineers, run pair sessions, and formalize best practices. Design CI/CD and automation processes using Azure DevOps and other tools. Oversee observability, reliability, and technical risk management. Collaborate with stakeholders on roadmap and criteria. Must Haves: 8+ years of experience in a Full-Stack role. Expertise in C#/.NET and solid backend design principles. Proven Azure architecture experience. Advanced SQL Server skills. Strong React experience. Nice to Have: Experience with Kubernetes and Terraform. Advanced knowledge of Power BI. Familiarity with Databricks/Spark for processing. Experience with event-driven integrations. Other Details: Location: Kraków, hybrid work environment. Contract type: Contract, with working hours from 09:00-17:00 CET.