C# and .net developer

Kajenthi@R ED Global - Senior Software Engineer (C#/.NET) - Freelance Contract - Mannheim - Hybrid

We are seeking experienced Senior Software Engineers (C#/.NET) with HW to join a major development project based in Mannheim, Germany.

Start Date: 20 November 2026

Language: English only (German not required)

Responsibilities

• Design, develop, test and maintain tool control software in C# and .NET
• Drive modularisation of a mature codebase without destabilising a production system
• Build robust concurrent code: multi-threading, locking and interlocking, parallelism in .NET
• Apply TDD and strengthen automated testing, including tests that touch real hardware
• Conduct code reviews; mentor and coach mid-level developers
• Troubleshoot complex issues across the software and hardware boundary

Must have

• Senior, hands-on C# and .NET on production systems
• Proven engineering experience in a hardware-related development environment — code that has controlled, driven or read from physical equipment
• Object-oriented design, SOLID, design patterns, Clean Code
• Test-Driven Development and ownership of automated test suites
• Multi-threading, locking/interlocking and parallelism in .NET
• Experience refactoring and modularising a long-lived legacy codebase
• Mentoring and code review experience
• English B2 or above. German not required
• Travel-ready for approximately 2 days per week on site in Mannheim, Germany
• Real-time systems and deterministic timing
• Hardware integration: motion control, sensors, actuators, device drivers, instrument interfaces
• Optical sensor data processing: spectroscopy, interferometry, imaging, signal processing
• Domain background in semiconductor, metrology, test and measurement, precision instrumentation, industrial automation or medical devices