Ingo (Dipl.-inform.) Grebe
Founder and Owner
Experience
Development of practice management software for appointments, including online booking
Reactive Systems
For a specialized diabetes center in Hamburg, I designed and independently implemented a custom practice software. The goal was to develop a fully integrated solution for managing appointments, patients, and practitioners – including online booking for patients.
Tasks and responsibilities:
- Architecture, design, and complete development of the web application
- Implementation of the user interface with Angular, SCSS, and Bootstrap
- Development of the backend with ASP.NET Core, REST APIs, and MS SQL
- Implementation of a role-based user concept for parallel use by medical staff
- Integration of an online booking system for patients
- Conducting all tests and close coordination with medical staff
- Agile approach using Scrum, including iterative planning and direct requirement clarification with doctors and staff
Results and impact:
- The software is used daily by up to 10 staff members at the same time and has noticeably simplified the practice's appointment management
- Patient online booking was successfully established and is used regularly
- The application impresses with intuitive usability and reliable performance
- High satisfaction from the practice management and team due to a practical, tailor-made implementation
Further development of a web application for vehicle inspections
GTÜ - Gesellschaft für Technische Überwachung
As part of a long-term project at GTÜ (Gesellschaft für Technische Überwachung mbH), I am involved as a full-stack developer in the further development of a modern web application that digitally supports vehicle inspections such as general inspections (HU) or safety tests (SP). The application is a core part of the company's newest software generation and is used nationwide.
Tasks and responsibilities:
- Implementation of new features on the frontend and backend with Angular and ASP.NET Core
- Identification and resolution of performance issues on the server side
- Development and optimization of logging mechanisms for improved traceability and error analysis
- Continuous refactoring of legacy code to ensure long-term maintainability
- Participation in architecture decisions and technical evolution of the overall system
- Close collaboration with QA, DevOps, and other development teams in an agile environment (Scrum/Kanban mix)
Results and impact:
- Active contribution to resolving critical performance issues in the backend as part of the performance team
- High customer satisfaction through fast and reliable implementation of new requirements
- Continuous onboarding into complex system parts and stable delivery of high-quality code
PWA for time tracking and CMS for managing employees and time entries
Reactive Systems
For a construction company from Wetzlar, I planned and fully developed a progressive web app (PWA) for mobile time tracking and a web-based CMS for managing employees, job sites, and time entries. The goal was to provide a user-friendly solution that works reliably in both online and offline modes.
Tasks and responsibilities:
- Architecture, design, and full implementation of the application
- Frontend development with Angular and SCSS with special focus on offline capabilities
- Backend implementation with ASP.NET Core, Entity Framework Core, and MS SQL
- Building a CMS for managing employees, job sites, and time entries
- Integration of a synchronization logic for offline use of the PWA
- Close coordination with the owner and staff for practical implementation
- Iterative approach using Scrum with regular feedback and direct testing in day-to-day operations
Results and impact:
- Over 40 employees use the app daily on job sites even without an active internet connection
- The software was easily adopted by all employees due to its intuitive usability
- The owner was extremely satisfied with the quick implementation and precise functionality of the solution
- The application sustainably digitalized and simplified time management in the company
Mobile app for conducting and logging COVID-19 antigen rapid tests
Reactive Systems
- Technologies: Angular, Bootstrap, HTML, NativeScript, SCSS, TypeScript
Further development of a web application for submitting medical invoices
Reactive Systems
- Technologies: AngularJS, Bootstrap, CSS, HTML, Java, JavaScript, SCSS
Web application for creating and publishing ad campaigns
Reactive Systems
- Technologies: Angular 5, ASP.NET, Facebook API, Google APIs, HTML, JavaScript, C#
Further development of a web application for submitting doctor invoices
Reactive Systems
- Technologies: AngularJS, Bootstrap, CSS, HTML, JavaScript, SCSS
Development of website, API, and database for real estate presentation
Reactive Systems
- Technologies: Angular 4, ASP.NET Core, Bootstrap, C#, Entity Framework Core
Further development of software for reward shops
Reactive Systems
- Technologies: AngularJs, ASP.NET WebAPI, C#, CSS, HTML, JS, Entity Framework, SQL
Development of software for particle measurement in cleanrooms
Reactive Systems
For an engineering firm in Langen, I developed custom software that digitally maps the entire process of particle measurement in cleanrooms – from managing measurement tasks, rooms, and limit values to mobile execution and post-processing of measurements. The application supports both office and field use and was specifically tailored to cleanroom technology requirements.
Tasks and Responsibilities:
- Planning and full implementation of the application including architecture design
- Development of a back office system with ASP.NET MVC and Entity Framework
- Implementation of the user interface with AngularJS, Bootstrap, and classic web technologies (HTML, JS)
- Implementation of the mobile app for offline execution of particle measurements on site
- Development of synchronization logic to transfer measurement data to the central server
- Close collaboration with the owner and technical staff for continuous optimization
- Agile approach following Scrum with iterative deliveries and practical validation
Achievements and Impact:
- Daily use of the software by over 10 employees – both in the field and in the office
- Offline functionality enables reliable execution of measurements directly at the customer
- The application was quickly adopted by the entire team due to its intuitive operation
- Significant improvement in efficiency and data quality in particle measurement and post-processing
Development of facial recognition software
Reactive Systems
- Technologies: AngularJs, ASP.NET WebAPI, C#, CSS, HTML, JS, Neurotechnology SDK, WCF
Further development of a geographic information system
Reactive Systems
- Technologies: Angular, ASP.NET WebAPI, HTML, JavaScript, Material Design, SCSS
Development of a reporting system
Reactive Systems
- Technologies: ASP.NET, C#, SQL Reporting Services
Summary
Since 2007 I have been working with great passion as a software developer and software architect in desktop and web development. As a consultant I help improve the quality of my clients' software. My specialty is developing web-based business applications. I build backends in C# using the Microsoft .NET Framework as services or APIs. They usually run in the cloud and on local intranets. The frontends are developed in JavaScript/TypeScript, HTML and (S)CSS with Angular and can be used on browser-capable systems. My strengths lie in independent and responsible thinking and acting.
Since 2007 I have been working with passion as a software developer and software architect in desktop and web development. As a consultant I increase the quality of my clients' software. By founding Reactive Systems I aim to take responsibility for larger projects and support junior developers.
Skills
- Angular And Angularjs
- Asp.net Core
- Asp.net Mvc And Webapi
- Bootstrap
- Entity Framework
- Jquery
- Nativescript
- Wcf
- Winforms And Wpf
- C#
- Fdo
- Javascript
- Html
- Razor
- (S)css
- Sql
- Sql Server
- Sql Reporting Services
- Typescript
- Azure Devops
- Git
- Jira
- Npm And Nodejs
- Team Foundation Services
- Visual Studio
- Webstorm
Languages
Education
Diploma in Computer Science · Computer Science
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