About us Optimus 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 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 Giessen, Koblenz, and Berlin. Tasks Design, 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 9, ASP.NET Core, EF Core, Angular 19, RxJS, NgRx, REST, microservices, and Azure cloud services. Develop loosely coupled, resilient architectures designed for long-term scalability. Profile 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 (C1 level).