Senior C#/.NET Developer / Software Architect – Legacy Device Software Modernization – HH

Project overview

OCENOX is a 360° consultancy from New Zealand, covering training, coaching, consulting, and implementation. For a client in the industrial sector, we are looking for on-site support in Hamburg.

You will further develop an existing desktop and web application, work closely with the client's internal software architect on the code, and bring the team along.

Responsibilities

What you bring

Plus Points

What makes the role special

You will contribute to development yourself, setting standards for code quality and helping the team make architectural decisions independently. We are not looking for a pure whiteboard architect or an Agile Coach, but someone who enjoys conceptual work and implements the results themselves.

• You will make architectural and design decisions at the code level together with the team and document them comprehensibly (e.g., as ADRs)
• You will implement architectural concepts into production-ready code, through pair and mob programming with the team
• You will modernize the existing software step by step: modularization, decoupling, replacement of outdated components
• You will secure existing behavior through automated tests and meaningful device simulators
• You will conduct architecture, design, and code reviews and pass on best practices to the team
• You will implement quality and security requirements in the code, also with regard to the Cyber Resilience Act
• You will help shape technical standards and guidelines for the use of AI tools in development
• At least 5 years of experience with C# / .NET in larger desktop or web applications
• Experience as a software architect, tech lead, or senior developer with architectural responsibility
• Practical experience with the modernization of established codebases (refactoring under test protection, step-by-step replacement)
• Confident handling of testing methods (unit, integration, system tests)
• Experience with code reviews and knowledge transfer within the team
• Very good German language skills, good English language skills
• You can be on-site in Hamburg 2–3 days per week
• WPF and MVVM
• Device software, measurement technology, laboratory automation, or hardware-related development
• AI-assisted development with Claude Code, GitHub Copilot, or comparable tools
• Security by Design, experience with regulatory requirements (e.g., CRA)
• Experience collaborating with offshore teams

Project details

• Start: ASAP / 01.11.2026
• Duration: 6 months, extension possible
• Workload: 3–5 days per week
• Location: Hamburg, with 2–3 days per week on-site, the rest remote
• Contract Type: Freelance
• Project Language: German, English also used within the team
• Start: ab sofort
• Duration: 6 Monate
• Remote: hybrid
• Location: Hamburg, Deutschland, DE
• Languages: German