// Computer Scientist (Diplom Informatiker FH)
Curriculum Vitae
# Profile
Senior software developer and architect with more than 20 years of experience, specialized in scalable JVM backends in Kotlin (Spring Boot, Micronaut, Ktor). I design, implement and document REST APIs for high-throughput systems, work test-first following clean code and design pattern principles, and structure domains according to DDD and hexagonal architecture. Experience with full-text search and indexing of large document collections, with event-driven architectures (Kafka, event sourcing) and with cloud operations on AWS and Azure. I am currently deepening my knowledge of embedding models, vector representations and machine learning (Python, PyTorch) in a structured continuing education programme.
# Skills
Backend & Web Services
Search & Recommendation
Security & Telematics
Cloud & DevOps
Architecture & Methods
Data & AI
Mobile · iOS / Android
° from continuing education / self-study, no project use
# Industry Domains
# Education
# Teaching & Continuing Education
# Core Areas and Frameworks
Spring / Spring Boot
- ✓ Experience with Spring and Spring Boot using Kotlin
- ✓ Scalable and efficient applications with Spring Framework
- ✓ RESTful APIs with Spring Boot and Kotlin
- ✓ Microservices architectures with Spring Cloud
- ✓ Spring Data JPA for database integration
Kotlin
- ✓ Kotlin Multiplatform (KMP) for cross-platform development
- ✓ Compose Multiplatform UI Framework
- ✓ Ktor HTTP client and server framework
- ✓ Coroutines for asynchronous programming
- ✓ Kotlin Multiplatform Mobile (KMM)
iOS / Swift / SwiftUI
- ✓ SwiftUI with Combine and Async/Await
- ✓ CoreData and RealmDB for local data persistence
- ✓ Swift Package Manager
- ✓ UIKit and Xcode development environment
- ✓ Unit testing and debugging
AWS
- ✓ AWS Lambda for serverless functions
- ✓ AWS S3 for data storage
- ✓ Complex AWS architecture design
- ✓ AWS Amplify for mobile backends
Vaadin
- ✓ Vaadin Flow (Java-based)
- ✓ Responsive and cross-platform web applications
- ✓ Integration with Spring Boot and Java EE
- ✓ Vaadin Designer and Vaadin Testbench
# Competency Matrix · Periods of Use
Detailed breakdown of the competencies applied in the projects. The periods refer to the documented use in the project history; “ongoing” marks competencies that are part of everyday work across projects.
Backend & Web Services
- Kotlin
- 2018–2026
- Java / Java 21
- 2000–2025
- Spring Boot
- 2018–2025
- Micronaut
- 2025–2026
- Ktor
- 2025–2026
- Kotlin Coroutines / Concurrency
- 2020–2026
- REST API Design
- 2018–2026
- OpenAPI / Interface Documentation
- 2018–2026
- API Versioning
- 2025–2026
- SOAP / WSDL
- 2024–2026
- Kafka / Event-Streaming
- 2018–2022
- Event-Sourcing
- 2021–2022
- Microservice Architecture
- 2021–2024
- High Load & Scalability
- 2018–2026
- JPA / Hibernate
- ongoing
- Vaadin 24
- 2025
Data & Persistence
- Data Modelling (relational)
- ongoing
- Domain & ER Modelling
- ongoing
- SQL & Query Optimisation
- ongoing
- Schema Migration (Flyway / Liquibase)
- ongoing
- PostgreSQL
- 2025–2026
- MS SQL Server
- 2025–2026
- Oracle
- 2016–2018
- MySQL / MariaDB
- 2000–2002, 2020
- IBM DB/2
- 2016–2018
- RealmDB / Local Persistence
- 2025
- ETL & Transformation Pipelines
- 2023
- XML / XSLT
- 2023
- Machine & Sensor Data (OPC-UA)
- 2023–2024
- Analytics & Usage Data
- 2021–2022
Architecture & Methods
- Domain-Driven Design
- 2025–2026
- Hexagonal Architecture
- 2025–2026
- Design Patterns
- ongoing
- Clean Code
- ongoing
- Test-Driven Development
- 2024–2026
- Unit & Integration Testing
- ongoing
- Code Reviews & Test Coverage
- 2022–2026
- Refactoring & Legacy Modernisation
- 2021–2025
- Monolith Decomposition / Domain Slicing
- 2021
- Specification-Driven Development
- 2024–2025
- Technical Documentation
- ongoing
- Scrum / Kanban / SAFe
- ongoing
- Onsite / Offshore Coordination
- 2016–2018
- Knowledge Transfer & Teaching
- 2015–2020
Cloud, Operations & CI/CD
- AWS (S3, EC2, Lambda, ECR/ECS)
- 2021–2026
- AWS Amplify
- 2025
- Azure
- 2023–2024
- GCP°
- basic knowledge
- Docker / Containerisation
- 2023–2026
- Kubernetes
- 2023–2024
- GitLab CI/CD
- 2025–2026
- Jenkins
- until 2022
- Git / Rebase Workflow
- ongoing
- Maven / Build Automation
- ongoing
Security & Telematics
- Cryptography & PKI
- 2024–2026
- Signature Verification (CMS/PKCS#7)
- 2024–2026
- mTLS / Certificate Handling
- 2025–2026
- Smartcard / eGK
- 2021–2025
- Telematics Infrastructure (gematik)
- 2021–2026
- Konnektor Integration
- 2025–2026
- OIDC / OAuth2 (Keycloak)
- 2022–2026
- Identity & Access Management
- 2022–2026
- Regulated Environments (Healthcare)
- 2021–2026
Search, Recommendation & AI
- Full-Text Search & Indexing
- 2018–2020
- Elasticsearch / OpenSearch
- 2018–2020
- Relevance Ranking
- 2018–2020
- Query Processing & Faceting
- 2018–2020
- Event-Driven Index Updates
- 2018–2020
- Agentic AI / Claude Code
- 2026
- Vector Search & Embeddings°
- since 2025
- Embedding Models (SBERT)°
- since 2025
- Cosine Similarity / Vector Spaces°
- since 2025
- Python (NumPy, pandas)°
- since 2025
- PyTorch / Neural Networks°
- since 2025
- Linear Algebra & Calculus for ML°
- since 2025
Mobile · iOS / Android
- Swift / SwiftUI
- 2021–2026
- UIKit
- ongoing
- Combine
- 2021–2026
- Objective-C
- 2014–2015
- Jetpack Compose
- 2022–2026
- Kotlin Multiplatform
- 2025
- Compose Multiplatform / Desktop
- 2021, 2025
- Offline Capability & Synchronisation
- 2025
- Release & Store Processes
- since 2022
° from continuing education / self-study, no project use
Projects
Healthcare (Gene Sequencing)
November 2025 – presentSenior Software Developer / Architect
Scalable Kotlin backend for processing and analyzing genetic sequencing data, connected to the German telematics infrastructure. Hexagonal architecture and DDD — core domain logic framework-independent and fully testable, developed test-first. Design, versioning and OpenAPI documentation of the REST interfaces (migration of the controllers to /api/v2). Concurrent, asynchronous processing with Kotlin coroutines and event-driven cache invalidation for latency-critical queries. Integration of the RKI trust center via Konnektor services (SOAP/WSDL, mTLS, CMS/PKCS#7 signature verification). Deployment on AWS EC2 with GitLab CI/CD.
AI / Machine Learning Training
October 2025 – presentSelf-directed
Structured continuing education on neural networks, embedding models and vector representations — including the mathematical foundations (linear algebra, calculus). Hands-on work with Python, NumPy and PyTorch, among other things the implementation of a custom GPT-style ChatBot.
Kotlin Multiplatform Training
October 2025 – presentSelf-directed
Prototyping cross-platform mobile apps with KMP. Native UIs (SwiftUI, Jetpack Compose), shared backend in Kotlin, cloud integration with Firebase and AWS.
Retail / Consumer Goods (Rossmann)
June 2025 – October 2025Senior Software Developer
Refactoring and theming of the master data portal according to design specifications, in close coordination with the design team. CSS adjustments and Vaadin code refactoring.
Integrated Communications Agency
May 2025 – October 2025Senior Software Developer, Software Architect
Development of a multiplatform app for iOS and Android with KMM. SwiftUI and Jetpack Compose UIs, RealmDB, AWS Amplify, Python data processing.
Healthcare / Telematics Infrastructure
August 2024 – April 2025Senior Software Developer / Architect
Reference implementation of “Proof of Patient Presence” (PoPP) for the nationwide German telematics infrastructure. Security-critical services in Java 21 / Spring Boot: cryptography, PKI, signature creation and verification. Specification-driven interface design including documentation — the implementation serves third-party vendors as a reference. Integration of eGK smart cards and SOAP services, developed test-first throughout against a public specification.
Optical Industry
November 2023 – April 2024Senior Software Developer
Development of an automated material tracking solution for production control. IoT and OPC UA integration.
Energy Supply
June 2023 – October 2023Consultant, Software Developer
Design and development of a configurable parser for analyzing and transforming business data from a gas trading system.
Healthcare (116117 App)
July 2022 – presentQA, Architecture Consulting
Quality assurance and architecture consulting for a nationwide health app. Code reviews, best practices, pull request processing.
Retail B2B (Hardware Stores)
July 2022 – March 2023Senior Developer, Backend
Development and maintenance of various backend solutions and iOS apps in the retail B2B space.
Automotive (Porsche Digital)
September 2021 – March 2022Senior Developer
Development of an app and backend for digitalizing customer-facing sales processes. Event sourcing, analytics, microservices.
Healthcare (Electronic Health Record)
July 2021 – September 2021Senior Developer
Design and implementation of a desktop client for the electronic patient record. Smart card integration on MacOS.
Education / Finance
January 2021 – August 2021Senior Developer
Design and implementation of microservices as core elements of a monolith-to-microservices migration.
Market Research
December 2020 – January 2021Developer
Development of an iOS SDK as a CocoaPod for a market research platform.
Tourism
July 2020 – November 2020Software Developer
Design and development of a microservice for managing available accommodations as a "single source of truth".
Education (DHBW Mannheim)
September 2015 – September 2020Lecturer
Teaching mobile application development on iOS with Swift. Creating teaching materials, demos and supervising student projects.
Healthcare (iPad App)
March 2020 – June 2020Software Developer
Design and development of an iPad app for first responder CPR training and emergency measures education.
Pharmaceuticals (Digital Library)
December 2018 – March 2020Software Developer, Consultant
Internal research and library system for medical literature search — search across a large body of scientific documents. Building and maintaining the full-text search index across distributed source systems, query processing, faceting and relevance ranking of result lists. Kafka-based, event-driven index updates; REST search interfaces as the central access point for internal applications, designed for concurrent access by many domain users.
Chemical Industry
October 2016 – December 2018Java Onsite Coordinator, Software Developer
Coordination with offshore teams in India. Development of projects in security self-service and compliance.
Automotive (Compliance)
February 2016 – September 2016Developer
Development and prototyping of a compliance web application. Integration of reporting frameworks, GUI development with Vaadin.
Sports (Nike USA)
March 2014 – April 2015Software Engineer, Consultant
Co-development of an iPad app for Nike USA. Frontend in Objective-C/iOS, backend in Java with Spring Framework and JBOSS.
Internet Startup (Berkeley, CA, USA)
2000 – 2002Architect, Developer, Co-Founder
Design and implementation of a social network platform for mapping and utilizing social networks. Middleware development with Tomcat and JBOSS.