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.