About usOptimus Search has partnered with one of Germany’s leading product-based companies focused on energy efficiency and the reduction of CO₂ emissions, contributing to a more sustainable future. Due to significant success over the past five years, the company is currently in a phase of hyper-growth, offering a clear path for career advancement. They are now seeking Senior Fullstack .NET Developers to join newly formed teams responsible for modernising legacy systems and building a new software architecture using the latest .NET 9 technology. The company has offices in Dresden, Bremen, and Köln.TasksDesign, develop, and document the architecture of a newly acquired product and integrate standardised software solutions.Extract components from a legacy system and migrate them to modern, cloud-based platforms.Coordinate and manage system interfaces in collaboration with cross-functional teams.Engage in full-stack development using C#.NET 8/9, ASP.NET Core, EF Core, React, REST, Microservices, and Azure cloud services.Develop loosely coupled, resilient architectures designed for long-term scalability.Profile3+ years experience within Software Development (C#).A passion for software engineering in a cloud-native environment.Hands-on experience with Domain-Driven Design (DDD).Strong focus on code quality and test-driven development (TDD).Excellent communication skills.Willingness to take operational responsibility within the team.Fluency in German (B1 minimum) and solid English skills (also C1 level).