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# Senior Software Engineer C# / .NET

- **Company:** NEW Gruppe
- **Location:** Mannheim, Germany
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Clean Code Principles, .NET Framework, Multitier Architecture, Automation of Tests, Unit Testing, C Sharp (Programming Language), Code Review, Continuous Integration, Relational Databases, Distributed Systems, Fault Tolerance, Hardware Design, Object-Oriented Software Development, Mockito, Software Engineering, UML, Data Processing, Multithreading, Real Time Systems, Information Technology, Front End Software Development, Restful APIs, Microservices
- **Published:** October 16, 2026
- **Apply:** https://www.adzuna.de/details/5929169874

## About the Role

* Deep, hands-on knowledge of C# 14 and modern .NET
 * Several years of experience with multi-threaded programming
 * Several years of experience with high-volume in-memory data processing
 * Solid experience designing and implementing RESTful APIs
 * Strong command of OOP, SOLID, Clean Code, multi-layer architecture and TDD
 * Practical experience with automated testing: unit tests, component tests, mocking
 * Good working knowledge of UML
 * Proven experience in hardware-related software development
 * Degree in Computer Science, Software Engineering, Physics or a related field
 * Excellent English; you work well in international, cross-functional teams

Nice to have

 * Real-time systems, hardware integration or optical sensor data processing (strong plus)
 * Legacy modernization, such as migrating a monolith to distributed, service-oriented systems or microservices
 * Distributed system design: event-based and object-based architecture, fault detection, causality methods, fault tolerance
 * Relational database design
 * Front-end development with .NET MAUI
 * German language skills

## Description

* Design, develop, test and maintain scalable applications in C# and the .NET ecosystem
 * Write clean, well-documented code following Clean Architecture and the team's coding standards
 * Work test-driven (TDD) and strengthen a culture of automated testing
 * Build robust multi-threaded solutions using locking, interlocking and parallelism in .NET
 * Turn business requirements into technical solutions together with product owners, architects and cross-functional teams
 * Review code and give constructive feedback to keep quality and consistency high
 * Mentor junior and mid-level developers and provide technical guidance
 * Identify and drive improvements in architecture, performance, reliability and maintainability
 * Troubleshoot and resolve complex issues across a distributed software stack
 * Contribute to CI/CD and modern delivery practices