Software Development & Architecture

by Janis Pütz

Hi! I'm Janis E.H. Pütz, a software developer & architect from Osnabrück, Germany.

I build maintainable web applications with C# / .NET & Blazor, and use clean architecture to keep software easy to evolve.

C#.NET 10Blazor Clean ArchitectureDDD / CQRSAI-assisted
Get in touch Open to select freelance & advisory projects — from €120/h
Janis E. H. Pütz

13+ years of experience building web applications

10+ years of experience with C# & .NET
  • C# 14
  • .Net 10
  • ASP.Net Core
  • Entity Framework Core
  • UI: Blazor (Server & Hybrid) & Razor Pages
  • .NET MAUI
  • SignalR
Master of Science in Information Systems
  • Studies at the University of Osnabrueck, Germany 2007 - 2012
  • Bachelor of Science in Information Systems (2011)
  • Master of Science in Business Informatics (2012)
  • Semester abroad at the University of South Florida (2009)
  • Integration of complex applications in ETL processes of data warehousing (2011)
  • Use of artificial neural networks for cloud computing (2011)
  • Conception and prototypical implementation of a meta-operator for the application and evaluation of alternative classification methods for the open source data mining tool RapidMiner (2012)
Experience in software architecture
  • Clean Architecture
  • Design Patterns
  • API-Design
  • DDD (domain driven design)
  • TDD (test driven development)
  • DRY - Don't repeat yourself
  • SOLID principles
  • Single-Responsibility
  • Open-closed principle
  • Liskovsche Substitution
  • Interface-Segregation
  • Dependency-Inversion
  • CQRS (Command-Query-Responsibility-Segregation)
  • Hexagonal architecture (ports and adapters)
Since 2024: Nature Robots (robotics)
  • Employed since October 2025 (freelance since Nov 2024)
  • Robot navigation UI development
  • Backend: Django (Python), PostgreSQL
  • Frontend: Next.js & React (TypeScript)
  • Docker
2022–2024: Futurepath / CARIAD (Volkswagen Group)
  • Development of a C# .NET 6/8 web application (license management)
  • Backend: EF Core (Code First)
  • Frontend UI: Blazor Server
  • Unit tests & integration tests using xunit, bunit, Moq & FluentAssertions
  • Staging environment & deployment for IIS
  • Micro-Services
  • Excel Imports & Exports using ClosedXml
2020 to 2022: Project for M-Soft
  • Further development of the .NET web application in C# & update to .NET 6
  • Backend: Repositories using EF Core (Code First) & DB, Indexer, Lucene Search
  • Frontend UI: ASP.Net Core, Blazor Server & Razor Pages
  • Programming support through paired programming
  • Security, Password Hashing, AccessToken
  • Development of coding guidelines
  • DevOps & Pulumi
2018 to 2020: Project for Brunel (M-Soft)
  • New development of a DMS (Document Management System) with C#, .Net 4.7 & Asp.Net Core
  • .Net Core 2.2.
  • Team planning of further development in sprint meetings
  • Debugging and troubleshooting
2015 to 2018: Project with Motion Media GmbH
  • New development of a web service for the creation of virtual tours
  • Architectural planning of the new application
  • Development of this application
  • Debugging and troubleshooting
2013 to 2015: Project for Gebit Münster
  • C# further development of a generalized catalog system
  • CQRS architecture (Command-Query-Responsibility-Segregation) in conjunction with an event store
  • Further development of the existing application
  • Further development and debugging