Karl Forstner - Software / Data Engineer

Q: Where is Karl based?

Karl is based in Gleißenfeld, Austria and prefers 100% remote projects.

Q: What languages does Karl speak?

Karl speaks the following languages: German (Native), English (Intermediate) .

Q: How many years of experience does Karl have?

Karl has at least 4 years of experience. During this time, Karl has worked in at least 9 different roles and for 7 different companies . The average length of individual experience is 4 months . Note that Karl may not have shared all experience and actually has more experience.

Q: What is Karl's latest experience?

Karl's most recent position is Automated development of processes for XML invoice formats at CIO.pro e.U. .

Q: What companies has Karl worked for in recent years?

In recent years, Karl has worked for CIO.pro e.U. , Forstner Software Solutions e.U. , ONE-PATH Solutions | ONE-CODE , Onecept GmbH , and Techexx GmbH .

Q: Which industries is Karl most experienced in?

Karl is most experienced in industries like Information Technology , Retail , and Sport . Karl also has some experience in Media and Entertainment .

Q: Which business areas is Karl most experienced in?

Karl is most experienced in business areas like Information Technology , Product Development , and Business Intelligence . Karl also has some experience in Project Management , Quality Assurance , and Strategy .

Q: Does Karl have any certificates?

Karl has 5 certificates . Among them, these include: Microsoft Applied Skills: Improving Agents with Autonomous Capabilities , Microsoft Applied Skills: Classes, Properties, and Methods in C# , and Microsoft Applied Skills: Developing an ASP.NET Core Web Application That Uses an API .

Recommended expert

Gleißenfeld, Austria

Check rate

Experience

Nov 2025 - Present

9 months

Automated development of processes for XML invoice formats

CIO.pro e.U.

Automated reading and validation of XML invoice formats (e.g. ebInterface, UBL, EBOR)
Structured transfer of data to an ERP system
Implementation with .NET and C#

Sep 2025 - Present

11 months

Founder | Software Engineer / Architect

Forstner Software Solutions e.U.

Development of custom .NET and C# software solutions
Modernization of existing systems from concept and development to cloud deployment in Azure
Focus on high-performance, future-proof B2B software with AI-powered features
Close collaboration with customers to improve business processes and increase efficiency

Sep 2025 - Present

11 months

Software Engineer

ONE-PATH Solutions | ONE-CODE

Technical implementation of ONE-PATH as part of ONE-CODE.ONE
Development of secure, scalable applications from prototypes to production-ready systems
Architecture and programming of platforms
Integration of data and knowledge
Development of AI-powered solutions for everyday work

Sep 2025 - Present

11 months

One-Hub development of a scalable data hub

Onecept GmbH

Development of a scalable data hub in the ONECEPT ecosystem for data integration and structuring
Focus on modular architecture, API connection, and Blazor-based frontends
Integration of AI features such as semantic search (RAG), role and user management
Flexible deployment options (cloud or on-premise) and GDPR-compliant use

Jul 2024 - Aug 2025

1 year 2 months

Kiway web application with AI

Techexx GmbH

Architecture, concept, and implementation of a large web application for internal process mapping with AI
Independent implementation of frontend, backend, and data model
Deployment in Azure including migration from the self-hosted environment
Technologies: ASP.NET Core Web API, .NET Blazor WASM, MudBlazor, SignalR, Azure Container Apps, PostgreSQL, Playwright.NET, xUnit

Jul 2024 - Aug 2025

1 year 2 months

Software Engineer

Techexx GmbH

Design, architecture, and development of business software based on ASP.NET Core Web API, Blazor WebAssembly, and PostgreSQL
Programming in C# and JavaScript
Data modeling and API integration
Project coordination with Jira
Deployment with Docker and Azure Container Apps
Quality assurance through unit and integration tests (Playwright.NET, xUnit)

Jan 2024 - Mar 2024

3 months

MS SQL Server Migration

Mediashop GmbH

Migration of MS SQL Server 2016 to 2022, including SSIS and SSAS upgrades
Adapting database drivers and developing new logic for changed data type return values

May 2023 - Feb 2024

10 months

FitMatch App Development

Privater Kunde

Development of an app to connect sports-minded people, with a focus on shared activities and social interaction
Involvement in concept, UX/UI, frontend and backend development, as well as market analysis and strategy
Integration of premium features, event bookings, and personalized fitness data
Technologies: ASP.NET Core Web API, .NET MAUI Blazor, MudBlazor, Azure App Services, Azure PostgreSQL

Sep 2022 - Mar 2024

1 year 7 months

Software Data Engineer

Mediashop GmbH

Further development of the data warehouse and automation of data processes with SSIS and SSAS
Development of new logic to adapt to changes in data type return values
Creation of management reports and dashboards with Power BI
Optimization of SQL queries and automation of reporting processes to improve efficiency
Maintenance of the internal DWH

Sep 2022 - Jan 2024

1 year 5 months

ETL & Reporting Development

Mediashop GmbH

Development and automation of SSIS pipelines and reporting structures
Creation of reports with Power BI and maintenance of the internal DWH
Improving the efficiency and quality of data processes to support data-driven decisions

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Retail, and Sport.

Information Technology

Retail

Sport

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, Business Intelligence, Project Management, Quality Assurance, and Strategy.

Information Technology

Product Development

Business Intelligence

Project Management

Quality Assurance

Strategy

Summary

Karl Forstner combines modern software development with data engineering and technical system architecture. His focus is on building scalable platforms, applications, ETL pipelines, and data solutions, as well as integrating structured and unstructured data into productive enterprise systems. As the licensed managing director of ONECEPT GmbH and lead developer of the ONE-HUB product, he supports projects from concept and architecture through to production cloud and on-premise deployments.

Skills

.Net / Asp.Net Core
Full-Stack Development
Software Architecture
Blazor / C#
React
End-To-End Delivery Of Modern Web Applications
Modular, Scalable System Designs
Javascript / Rest Apis
Postgresql / Mssql
Etl Pipelines
Api Development
Data Integration And Transformation Processes
Rest Apis And Ssis / Ssas
System Integration
Docker / Azure
Hub Systems
Ai Integration
Signalr / Playwright.Net
Integration Of Data, Knowledge, And Processes
Ai-Powered Features For Businesses
Xunit

Languages

German

Native

English

Intermediate

Certifications & licenses

Microsoft Applied Skills: Improving Agents with Autonomous Capabilities

Microsoft Applied Skills

Microsoft Applied Skills: Classes, Properties, and Methods in C#

Microsoft Applied Skills

Microsoft Applied Skills: Developing an ASP.NET Core Web Application That Uses an API

Microsoft Applied Skills

Microsoft Applied Skills: Developing Generative AI Apps with Azure OpenAI and Semantic Kernel

Microsoft Applied Skills

Microsoft Applied Skills: Generating Reports with AI Research Assistants

Microsoft Applied Skills

Statistics

Experience

Total positions 10

Experience in Information Technology 3 y

Avg length 11 m

Longest experience 1 y 6 m

Expertise

Recent roles Automated development of processes for XML invoice formats, Founder | Software Engineer / Architect, Software Engineer

Main industries Information Technology, Retail, Sport

Main business areas Information Technology, Product Development, Business Intelligence

Qualifications

Certifications earned 5

Profile

Created

May 2026

Last Update

July 2026

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Frequently asked questions

Have questions? Find more information here.

Karl is based in Gleißenfeld, Austria and prefers 100% remote projects.

Karl speaks the following languages: German (Native), English (Intermediate).

Karl has at least 4 years of experience. During this time, Karl has worked in at least 9 different roles and for 7 different companies. The average length of individual experience is 4 months. Note that Karl may not have shared all experience and actually has more experience.

Based on recent experience, Karl would be well-suited for roles such as: Automated development of processes for XML invoice formats, Founder | Software Engineer / Architect, Software Engineer.

Karl's most recent position is Automated development of processes for XML invoice formats at CIO.pro e.U..

In recent years, Karl has worked for CIO.pro e.U., Forstner Software Solutions e.U., ONE-PATH Solutions | ONE-CODE, Onecept GmbH, and Techexx GmbH.

Karl is most experienced in industries like Information Technology, Retail, and Sport. Karl also has some experience in Media and Entertainment.

Karl is most experienced in business areas like Information Technology, Product Development, and Business Intelligence. Karl also has some experience in Project Management, Quality Assurance, and Strategy.

Karl has 5 certificates. Among them, these include: Microsoft Applied Skills: Improving Agents with Autonomous Capabilities, Microsoft Applied Skills: Classes, Properties, and Methods in C#, and Microsoft Applied Skills: Developing an ASP.NET Core Web Application That Uses an API.

Karl is immediately available part-time for suitable projects.

Karl's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.

To hire Karl, click the Meet button on the profile to request a meeting and discuss your project needs.