Last updated: August 2025
I'm open to opportunities and available for consulting, contracting, and freelance engagements. If you're interested, you can find more details here.
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Independent Contractor
Berlin • Remote • April 2025
Develop the technical foundation for a modern retail media platform, replacing legacy systems to provide advertisers with a scalable, flexible, self-service solution for ad management and targeting.
- Design and develop distributed microservices with Kotlin and Spring Boot
- Implement and maintain REST APIs for internal and external systems
- Integrate Kevel for dynamic advertising content delivery
- Build data workflows with Apache Airflow and manage databases with Liquibase
- Use Terraform and Kubernetes for basic infrastructure tasks and manage CI/CD pipelines with GitHub Actions and Docker
ING Germany
Independent Contractor
Nuremberg • Remote • July 2024 — March 2025
Web application for bank customer service to efficiently conduct all financial services by phone
- Developed and enhanced Java applications with new features and upgrades using Java, JEE, Spring, Hibernate, and SQL
- Adapted applications to regulatory and technical changes with Spring and Wicket
- Fixed bugs and ensured stability
- Implemented automated tests to ensure quality and compliance
- Integrated third-party systems and APIs via REST and web services
- Supported operations, builds, deployments, and database management
Biowink GmbH
Senior Software Engineer
Berlin • Remote • Sep 2022 — Apr 2024
Building and maintaining the iOS app Clue Period Tracker & Calendar
- Took part in the reimplementation of the existing app written in Objective-C, leveraging a modern stack with SwiftUI and adopting async/await programming paradigms.
- Assisted in backend development within a microservices architecture environment as needed, utilizing Kotlin.
- Contributed to streamlining the deployment process using fastlane in combination with GitHub Actions.
- Enhanced the continuous integration setup, resulting in a substantial reduction of UI test execution time.
- Coordinated the technical integration of data from Oura smart rings into backend systems. Developed data visualization features for sleep duration within the app using Swift Charts.
- Operated successfully in an international work environment, collaborating with colleagues from over 17 different countries. Worked within regulatory requirements in a medical setting, as the app is classified as a Class B medical device.
Exaring AG
Senior Software Engineer iOS
Munich • Hybrid • Sep 2017 — Jul 2022
Building and maintaining the iOS and tvOS apps for waipu.tv and O₂ TV
- Created the framework architecture and project setup enabling the development for various platforms and different brandings from a unified codebase.
- Developed and refined significant portions of the tvOS app.
- Held responsibility for a reliable video player.
- Implemented key features for the iOS app (the electronic program guide, a VOD media library, and user recordings).
- Invented a new login mechanism for big screens and coordinated with the development teams from other platforms. Helped with patent application process and invention documentation.
SISOL erneuerbare Energien GmbH
Independent Contractor
Nuremberg • Remote • 2016 — 2022
Development of a multilingual, cross-platform desktop application for ETIM classification and feature management.
- Designed and implemented the core architecture with Java, JavaFX, and Swing.
- Built an import solution for ETIM catalogues, enabling data processing across multiple versions and languages.
- Developed comparison and editing functionality for complex product attributes.
- Optimized database performance and data handling for large catalogues.
- Introduced automated testing and quality assurance practices.
- Contributed to agile delivery, requirement analysis, and stakeholder collaboration.
ING Germany
Senior Software Engineer & Tech Lead iOS
Nuremberg • On-site • Oct 2014 — Aug 2017
Building and maintaining the iOS banking app for ING Germany
- Oversaw team build up as first full-time iOS developer at ING Germany.
- Planned and implemented the basic infrastructure and project setup to support a modular app, allowing different ING departments to maintain and contribute core features.
- Implemented core functionality for transferring money directly within the app.
Gymder
Independent Contractor (Android, iOS)
Munich • Remote • Jul 2016 — Jul 2017
Contributed to the development of the Gymder fitness app, a social fitness tool that connects gym enthusiasts for workout partnerships. Collaborated on iOS and Android development to enhance user experience and functionality, focusing on turning workouts into social interactions.
ING Germany
Senior Software Engineer Java
Nuremberg • On-site • Apr 2012 — Sep 2014
Development of internal web applications for authorization management and call center agents
- Architecture and implementation of an IT platform for workflow-supported authorization management, utilizing current development tools and frameworks such as Spring, Hibernate, Wicket, JUnit, Mockito, and QueryDSL.
- Managed the provisioning and operation of the IT authorization platform in the production environment, including the Oracle Waveset Identity Manager.
- Took part in the conception and implementation of an internal web application for call center agents, used during customer calls to perform account operations after successful customer authentication. Technologies used include Wicket, Jenkins, Nexus, JUnit, Mockito, Spring.
- Ensured adherence to development guidelines and maintained software quality through automated IT tests
Schweizerische Bundesbahnen SBB
Independent Contractor (Java, OpenGL)
Berne, Switzerland • On-site • Jan 2012 — Mar 2012
Helped out with prototyping and performance tuning
- Prototype implementation of the train schedule rendering component for train dispatchers using OpenGL.
- Performance tuning of rendering and adjustments to the dispatcher client written in Java using Eclipse RCP.
Lumatix
Co-Founder & Lead Engineer
Erlangen • Hybrid • Sep 2010 — Jan 2012
Co-founded Lumatix and lead development of Lumatix Atrium Designer, a 3D real-time visualization middleware.
- Evaluation and implementation of various approaches and scientific publications on Real-time Global Illumination.
- Design and implementation of the graphics routine and core component of the product in C++, OpenGL, and OpenCL.
Spirit Link GmbH
Independent Contractor (Java)
Erlangen • Hybrid • Apr 2009 — Aug 2010
Technical consultation and implementation of various Java projects
- Consulting and implementation projects for Novartis on dotCMS with Java.
- Maintenance of a price list management tool using Java and Eclipse RCP for Siemens.
Spirit Link GmbH
Senior Software Engineer Java
Erlangen • On-site • May 2001 — Mar 2009
Technical management and implementation of multiple projects in the Java/JEE environment for companies such as Siemens AG, Novartis Oncology, and Areva NP.
- Development of Java-based web applications and rich-client applications.
- Architectural design, modeling, and programming. Leadership of project-specific development teams of up to 6 people.
- Areas of expertise include knowledge and document management, as well as medical image processing.
AKAD University
Diploma in Business Informatics (University of Applied Sciences)
Stuttgart, Germany • Sep 2005 — Apr 2009
Specialization: Computer-Integrated Systems, Software Development, Networking
Grade: Very Good (1.3)