Vaadin Experts in Germany

Medikamendo: E-health platform for digital repeat medication & follow-up prescriptions

• End-to-end implementation: UX conception, UI design, and frontend development for three connected portals (patients, medical practices, pharmacies).
• AI prototyping: Efficient creation of interactive prototypes using Figma and GitHub Copilot.
• Design system: Creation and continuous development of a consistent design system and UI components.
• Corporate design: Maintenance and further development of the consistent brand presence and websites.

• Developing the infrastructure and improving existing infrastructure: Jenkins, Gitlab Pipeline, OpenShift, Docker, Helm Chart, Kubernetes, Artifactory, CodePipeline, CodeArtifact, Python
• Documenting solutions in Jira/Confluence
• Supporting other colleagues in different technical areas

• Extension of OSGi modules in a complex communication solution
• Debugging communication with Wireshark and remotely in the JENS test environment
• Migration of tests from TestNG to JUnit 5 with Mockito and AssertJ
• Updating vulnerable dependencies and improving code quality
• Changes to the Vaadin frontend
• Increasing test coverage

• The goal of BIENE is to provide a unified tax collection program for all federal states.

• Tax collection involves collecting the taxes that have been assessed. This includes, for example, taking due dates into account, recording incoming and outgoing payments, and initiating reminders or refunds. Limitation periods and payment reminders are also important. BIENE handles all payment transactions with banks and accounting.

• Set up the architecture and coordinated the provision of development and test environments at the Hannover site

• Installed and configured the environments on Linux servers (Apache Kafka, PostgreSQL)

• Interface coordination: coordinated and aligned the connection of software products from other departments and their test data

• Migrated the application server, JDK, and Maven project structure

• Coordinated environments and managed builds

• Implemented external interfaces

• Delivered business requirements

• Designed and implemented RESTful APIs and OpenAPI specifications

• Designed and implemented a microservice architecture

• Set up and maintained CI/CD pipelines

• Deployed applications on OpenShift

• Created technical documentation and diagrams

• Worked with SQL databases (Oracle and PostgreSQL)

• Set up authentication and authorization for the application and users

• Containerized the application (automated deployment through the CI/CD pipeline)

• Development of a new generation of Spring Boot microservices for an archiving system on OpenShift, monitoring, security analyses

Stack: Java, Spring Boot, Kafka, Vaadin, OpenShift 4.x, Maven, Artifactory, Jenkins, Git/Github, GitHub Copilot, GitOps, CI/CD, Kargo/ArgoCD

• Spring Boot Software Engineer
• DevOps Engineer (Kubernetes, Azure DevOps)

Toolstack: Java, Spring Boot, Kubernetes, Helm, GitOps, ArgoCD, Docker, Azure DevOps, CI/CD Pipelines, Git, Postgres

• Overall technical responsibility for innovative SAP Customer Checkout solutions for leading customers such as Aramark, Consortium Gastronomie, Feinkost Käfer, TSG Hoffenheim, and VfB Stuttgart. End-to-end support from requirements analysis through implementation and support.

• Successful design and development of the NDS SmartPOS platform ("Läufer App"):

• Development of the software architecture and implementation according to Modern Android Development principles.

• Management of a small development team (1 Android expert, 1 working student) with a 50 % share of my own development work.

• Integration of various payment SDKs (S-Payment S-POS, VR Payment, CCV), enabling customers to achieve significant cost savings by continuing to use existing contracts.

• Successful rollout at several major customers, with demonstrably increased efficiency of sales staff.

• Independent development and successful implementation of critical infrastructure components:

• Reporting server (SQL, JasperReports): Demonstrable reduction in accounting workload by eliminating the need for daily manual data transfer to the ERP system.

• ZVT plugin: Sole responsibility for implementing the serial protocol with Java/Netty over TCP/IP, saving several thousand euros per site and successfully used in production at several Bundesliga stadiums.

• Complete independent development of specialized plugins and server applications for customized extensions of SAP Customer Checkout:

• Waiter Teams Plugin: Enables waiters to work and settle accounts as a team.

• SQL Reporting: Independently delivered from concept through complete documentation.

• RFID payment solution for employee cards: Responsible for the complete development cycle.

• Integration with reservation services: Designed seamless integration with Luca and other services and implemented it together with a colleague.

• Direct on-site technical support for customers, including rapid troubleshooting in real-time environments with high transaction volumes and direct coordination with stakeholders to continuously improve the systems based on practical experience.

• working in a team using an agile method (Scrum)
• Backend development in Java (Spring Boot)
• Frontend development in Angular

• Migration of the platform to X systems
• Analysis of changes related to TCP/IP communication
• Handling error tickets
• Installation and configuration of Xypro Security 1 attack detection
• Setting up an SNMP.v3 connection to send alert traps to Netcool (Tivoli)
• Installation and configuration of the RemoteAnalyst software
• Migration of master data and timetable data
• Setting up and monitoring MQ pipelines to external partners

• Further development of the existing e-commerce platform based on SAP Commerce (Hybris) to meet the growing demands of digital commerce.
• Ensuring the scalability and performance of the backend, so the platform remained stable and efficient even under heavy user load.
• Development and integration of new OCC REST APIs and services for modular extensions and flexible adjustments, to implement new features quickly.
• Optimization of data flows and interfaces, which significantly improved platform efficiency and system performance.
• Ensuring a maintainable and scalable code base by using Clean Code principles, proven design patterns, and a future-proof architecture.
• Reduction of errors through extensive testing with JUnit, Mockito, and load tests with Gatling, supported by the introduction of automated test processes.
• Improved system performance through targeted refactoring measures and efficient database queries, especially to handle peak loads.
• Use of modern cloud and monitoring tools such as Kubernetes, Google Cloud Platform (GCP), and Grafana to ensure a stable and monitored infrastructure.
• Clear improvement in efficiency, scalability, and reliability of the platform, which now meets the demands of a dynamic and growing e-commerce market.

• New development of the vehicle planning and delivery system (FAPS)

• As part of the modernization of a central backend application, the existing monolithic COBOL-based system was replaced by a service-oriented architecture with Spring Boot. The goal of the project is to make the digital mapping of vehicle planning and delivery future-proof and scalable.

• Work on the technical architecture and interface design

• Development of a service based on Spring Boot for migrating existing data into a new data model

• Development of REST APIs and the related service layer

• Development of middleware for integrating the new backend into an existing client

• Creation of unit and end-to-end tests

• Adaptation of build pipelines

• Developer training for customer staff (Java, Azure DevOps, general support)

• Support for testers and other project members

• Upgrade of the Spring Boot version (& Hibernate)

• Creation of documentation

• Java 8 and 17, Spring Boot, Spring JPA, Hibernate, Optimistic Locking (entity versioning), JUnit, Cucumber, PostgreSQL, Azure Cloud, Microservices, Azure Storage, Azure DevOps, Azure Kubernetes Service, RESTful web services, JSON, Scrum, Confluence, ArchUnit

The Helaba ATLAS project aims to modernize core systems and make them future-proof. As part of the subproject, the existing legacy system for international payments is being replaced by a modern web-based application.

• Analysis of functional and technical requirements
• Analysis and optimization of business processes
• Process modeling
• Preparation and facilitation of workshops
• Defining project scope and prioritizing requirements
• Business process management (analysis, modeling, and optimization)
• Specification of user stories
• Designing business and authorization concepts
• Testing and acceptance
• Designing mockups in Figma
• Creating the UI/UX style guide for web applications Approach: Scrum (agile) Technologies: Jira, Confluence, MS Teams, Conceptboard, Java, Vaadin, Figma

• Pilot testing local AI environments to explore local AI use cases and cloud-based AI solutions
• Evaluation of AI tools and techniques
• Use of local AI tools with own data sovereignty
• Prompt engineering
• Creation of example environments for speech-to-text, text-to-speech, text-to-image, text-to-video, and image-to-video

Tools: Grok, Perplexity, ChatGPT, Elevenlabs, Github, Ollama, HuggingFace, Open WebUI, Faster Whisper, LibreTranslate, WSL, Docker Desktop, Shotcut, Audacity, Sound eXchange, Ffmpeg, Coqui TTS, Pinokio, Stable Diffusion Web UI, ComfyUI, OWL, Void Editor

• Maintenance, further development, modernization and testing of the OK.VERKEHR specialist application, a monolithic Enterprise Java solution (with approx. 3,5 Mio LOC) for vehicle registration and driving license authorities
• Design, development, testing and maintenance of end-to-end workflows (dialogs, backend services and persistence layer, test suite) for new driving license applications, changes/extensions to driving licenses, management of parking permits and truck driver cards
• Development and maintenance of web services for communication between local traffic authorities and the Federal Motor Transport Authority, FAER register, TÜV testing centers and driving schools
• Performance optimization and targeted refactoring for the future migration to a cloud architecture and the addition of a new web client (Vaadin)
• 3rd-level support for customers during ongoing operations