Software Engineering Norbert WellnitzDE

Available for new projects from October 2026

Senior C#/.NET Developer for Industrial and Safety-Critical Systems

Degree in Electrical Engineering (Dipl.-Ing.). 20+ years of project experience in automotive, defence, e-government, and avionics. Scrum, DDD, clean code, TDD. Currently working with AI-assisted development.

Freelance C# Developer · ASP.NET · Senior .NET Consultant · Jever · Remote

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Core competencies

Tech stack recruiters can scan

  • Backend

    C#, .NET / .NET Core, ASP.NET, MVC, WebAPI, REST, WCF, SOAP, messaging systems

  • Desktop / UI

    WPF, UWP, WinForms, MVVM, event bus

  • Databases

    SQL Server, Oracle, PostgreSQL, LINQ, Entity Framework, NHibernate

  • Architecture

    SOA, DDD, TDD, SOLID, clean code, Scrum, distributed systems

  • AI

    Cursor, Claude Code, Ollama, Hugging Face, Python

  • Tools

    Visual Studio 2022, Git, TFS, NUnit, XUnit, Moq, Postman, Enterprise Architect

Automotive · Defence · Avionics · Automation engineering · Insurance · E-government

Project history

Four lead projects. Full list in the CV.

Siemens Nuremberg — SIDIS

May 2022 – present

Role:C# developer, SOA components

Tech stack:C#, Windows Forms, Git, message bus, FAZIT, ODX

Problem
In automotive final assembly, commissioning and ECU tests must run through loosely coupled components. Any downtime at test stations halts the production line.
Solution
Ongoing development and new builds of FAZIT and ODX components. Message-bus communication. Test software for final assembly and ECU testing.
Result
Production software in use at Siemens Nuremberg. Prior experience from the SIDIS rollout at VW/Audi do Brasil.

Rheinmetall Electronics — Soldier guidance system

Jan 2020 – Apr 2022

Role:C# / UWP / WPF developer

Tech stack:.NET 5, UWP, WPF, ESRI ArcGIS, MVVM, event bus, Google Protobuf, XUnit, Scrum

Problem
The German armed forces need a successor to IdZ. Locations and missions must be visible across distributed systems on screens and via IP radio networks.
Solution
Complex UI features: helmet compass calibration, geodata visualisation (ESRI), sensor integration, map elevation profiles. Used across roughly a dozen UWP apps plus WPF.
Result
Deliverable UI and sensor functions in a safety-critical command and control system.

City of Hamburg — Digital First

Sep 2017 – May 2019

Role:Software developer, knowledge lead in a Scrum team

Tech stack:C#, ASP.NET, MVC, REST, DDD, NHibernate, SQL Server, Swagger, Scrum

Problem
The city needed its first prototype online service. Domain-driven design and existing infrastructure made the onboarding slow.
Solution
Infrastructure and online services. Fast onboarding into DDD. Transition into a newly formed Scrum team. Point of contact for REST suppliers and DevOps until production readiness.
Result
Online service went live. GULP reference from the group leader, IT-Haus (2,700 employees), 22 May 2019.

VW / Audi do Brasil — SIDIS rollout

Jun 2014 – Oct 2015

Role:C# developer, on-site trainer

Tech stack:SIDIS Pro, C#, SQL Server, Oracle, CAN / K-Line / LIN, UDS, ODX/PDX

Problem
SIDIS had to be rolled out in São Paulo. ECU test programs and production protocols were missing locally. A production-line halt is expensive.
Solution
Test programs (CAN, UDS/PDX). Onboarding into internal software systems. Training of Brazilian teams in Portuguese.
Result
Played a key role multiple times in preventing final-assembly downtime. GULP reference from the project manager, VW Curitiba, 23 June 2015.

GULP references

Original letters, verified by GULP

City of Hamburg — Digital First

Sep 2017 – May 2019

Reference by group leader, IT-Haus (2,700 employees), 22 May 2019

In this project the consultant was deployed for 6 months as a software developer in the Servicekonto team, where he was able to familiarise himself very quickly thanks to his understanding of the domain-driven design used there. He impressed with his rapid comprehension, a structured working style, and extensive programming skills. To advance the development of the city of Hamburg's first prototype online service, he moved into a newly formed Scrum team. He soon became the go-to person for his colleagues as a knowledge lead and took on extensive responsibilities. Within the team he passed on many skills in MVC programming, was the contact for the external REST-API supplier, and helped operations/DevOps troubleshoot in downstream environments until the product reached production readiness. The consultant was also a personal asset to us with his balanced and consistently friendly personality. We recommend him without any reservation.

Volkswagen — Curitiba plant, Brazil

Jan – Jun 2015

Reference by project manager, Volkswagen Curitiba, 23 June 2015

Besides his extensive programming knowledge and a remarkably broad range of technical skills, the consultant impressed with his many ideas for solving the most diverse problems. On his own initiative he familiarised himself in the shortest possible time with the functioning and protocols of our internal software systems. With his knowledge and his high level of effort, he played a decisive role several times in preventing final-assembly downtime. Also noteworthy was the high quality of the employee training he conducted and his ability to integrate into our Portuguese-speaking team.

Third GULP reference

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About me

What it's like working with me

For over 20 years I have been working as an independent C#/.NET developer in industrial and safety-critical environments. I join the team as a developer, architect, or knowledge lead — not as a pure ticket executor.

I work in Scrum, write testable code (TDD, XUnit/NUnit), and leave behind systems the team can build on. References describe fast onboarding, structured work, and an unrestricted recommendation.

  • CompanySoftware Engineering Norbert Wellnitz
  • EducationDegree in Electrical Engineering (Dipl.-Ing.), Jade University of Applied Sciences, Wilhelmshaven (diploma: good; thesis: very good)
  • Work locationRemote. Hybrid possible in the Jever / Northern Germany area. Office also in Salvador, Brazil.
  • LanguagesGerman (native) · English (fluent) · Portuguese (fluent)
  • PositionsSoftware developer · Software architect · Tester · IT trainer

Contact

Project discussion within 24 hours

Briefly describe the role, the stack, and the timeframe. I typically reply within one day.

inwjever@zoho.com+49 160 97642660
  • Mobile BR: +55 71 996 790 906
  • 26441 Jever · Salvador, Brazil