DHFreelancer profile translated to English.
Back to original languageAbout Detlef
I am a certified Fullstack Developer and System Architect on the Microsoft platform. I have very good knowledge in building and integrating large systems, where some components are operated in the cloud and others on-premise. My knowledge includes how to retrieve and store information in both SQL and No-SQL databases, how associated microservices in the backend communicate with the database, and how the information is presented in the frontend via a Single Page Application (SPA) in the web browser. If necessary, parts can also be developed as desktop clients (WPF, XAML) or mobile clients with .NET Multi-platform App UI (.NET MAUI).
I enjoy working in a microservice-based architecture where each microservice is responsible for its own data. Programming is done in C#, .NET 9, and ASP.NET Core.
Programming against SQL Server can be done with Microsoft's Entity Framework or an ORM like Dapper. I develop in Visual Studio 2022. On the frontend, I prefer working with Blazor, but I have also worked with frameworks like Vue.js or Angular in conjunction with Visual Studio Code.
Source code management with GIT and automated builds (CI/CD) are handled via Azure DevOps or GitHub.
German
Native or bilingual
English
Fluent
Swedish
Native or bilingual
Remote only
Primarily works remotely
Experience
- Gilbarco Veeder-RootFullstack Developer and System ArchitectTECHMay 2023 - June 2025 (2 years and 1 month)Stockholm, SwedenGilbarco develops, among other things, a system called Epsilon, which is used to control fuel pumps at gas stations and to process credit card payments. It also offers functions for controlling hydrogen pumps, electric vehicle charging stations, and car washes. As part of the Epsilon project, I developed applications and integrations in a Windows 10/11 desktop environment. On the .NET side, this included maintaining applications on .NET Framework 4.8 as well as developing new applications with .NET 8/9. My C++ skills were also well utilized, as some subsystems are still developed in C++.Epsilon uses its own socket-based protocol to enable communication between the different subsystems via messages. I investigated whether this messaging service could be replaced by Azure Service Bus, RabbitMQ, or ZeroMQ.I also developed a .NET 9 client that could store time series data in AWS IoT Core via a custom-developed Cloud Connector. This included configuring a Docker container under WSL2 (Windows Subsystem for Linux 2).For communication with external systems – for example, for processing credit card transactions – classic REST interfaces were used.
- Tryg Forsikring A/SFullstack Developer and System ArchitectBANKING AND INSURANCEMay 2021 - May 2023 (2 years)Stockholm, SwedenIn 2021, I joined Tryg as part of a project at Moderna Försäkringar (Moderna Försäkringar is part of the Tryg group). I developed in both Progress OpenEdge 12 and C# with Microsoft .NET. The application developed by our team was used by insurance agents to manage corporate insurance.When the Danish company Tryg also acquired Trygg-Hansa, I was a member of the migration group responsible for transferring all corporate insurance from Moderna to Trygg-Hansa. I developed a program in C# that checked various data fields from Moderna's corporate insurances and mapped them to the corresponding fields at Trygg-Hansa. We aimed to automate this process as much as possible.During the transition phase from the Moderna to the Trygg-Hansa environment, I also trained about ten developers from Moderna, all with an OpenEdge background, in .NET and C#. The goal of the training was to help these developers get started with .NET, C#, and WPF so they could work more effectively in Trygg-Hansa's Microsoft .NET-based development environment.Later, I had the opportunity to become part of the team developing the CST (Customer Sales Tool). This tool is used extensively by insurance agents at Trygg-Hansa. The tool is web-based, with the frontend developed in Vue.js 3 and the backend developed in C# and Microsoft .NET. The backend uses both REST and WCF interfaces to access other services within Trygg-Hansa.
- Scania ABSystem Developer and System ArchitectTRANSPORTATIONNovember 2014 - October 2020 (5 years and 11 months)Södertälje, SwedenAt Scania AB, I held the roles of System Developer and System Architect. The website I worked on daily was called FMP and was accessible at https://fmp.scania.com (today: https://my.scania.com/home).I was responsible for the code for authentication and authorization of Scania's truck customers who had purchased a vehicle (at that time, around 500,000 trucks were networked). This microservice was called FMP Auth. FMP Auth uses OAuth2 to generate so-called JWTs (JSON Web Tokens), which serve as access credentials in the frontend to reach different areas of FMP.When I started at the end of 2014, the system was built on a few very large MS-SQL databases and virtual Windows servers in Södertälje – a typical monolithic architecture. The Windows servers were configured as either web servers or application servers. There was a build pipeline in Jenkins, and when a new version was to be released, several teams would meet in the evening to perform a manual deployment together.During my time there, we gradually transitioned so that each team implemented its own build pipelines and automatic deployments (CI/CD). Among other things, I set up a TeamCity server that built and packaged all code – for both frontend and backend.By the end of 2016, it became clear that the monolith had to be split to maintain database performance. At the same time, the company wanted to migrate to the cloud, and the choice fell on AWS. Therefore, the conversion of our classic .NET microservices to .NET Core-based microservices began, aiming to avoid virtual servers as much as possible and instead use serverless or container solutions.At the code level, I migrated FMP Auth to ASP.NET Core 3.1 and transitioned the original MS-SQL solution to a NoSQL solution on AWS.
Recommendations
Be the first to recommend Detlef
Help this freelancer shine by sharing your experience working together.
These freelancer profiles also match your criteria
Agatha Frydrych
Backend Java Software Engineer
4.7
(3)
2
Baptiste Duhen
Fullstack developer
4.6
(4)
5
Amed Hamou
Senior Lead Developer
4
(2)
7
Audrey Champion
Web developer
4.3
(3)
4
Education
- AZ-204: Developing Solutions for Microsoft Azure2024AZ-204: Developing Solutions for Microsoft Azure
- as MCT, Microsoft Certified Trainer2024als MCT, Microsoft Certified Trainer