Jakarta Server Pages (JSP) Experts in Germany

• Creating concepts and architecture for domain integration (SEAT into the VW structure)
• Domain trusts and administration
• Operation and administration of Windows 2022/ 2025 servers and domains
• Domain restructuring
• GPO and SG editing and migration
• DNS restructuring and migration

Technologies: Windows 2022, Active Directory, ADFS, AD Azure Connect, DHCP, DNS, GPO, VMWare vSphere, Hyper-V, Powershell, Jira, MS Office 365,), SCCM, VSAN Fileservices, Approximately 800 servers, 400 users

• Modernization of a large-scale Java enterprise application*

The project is modernizing a complex enterprise application that has grown over many years. The existing Spring-based legacy system runs on Java 8, OSGi, and Eclipse RCP and is being gradually migrated to a modern, maintainable architecture with Java 25 and Quarkus.

Marcus works on analysis, architecture, refactoring, and implementation. One focus is on untangling historically grown structures and dependencies and on building a clean, sustainable Java and Quarkus technology stack.

Tools & technologies: Java 8, Java 25, Quarkus, Hibernate ORM with Panache, EclipseLink, OSGi, Eclipse RCP, Maven, JUnit, Mockito, REST, JSON, Git, Eclipse IDE, IntelliJ IDEA Ultimate, Jira, Confluence

• Implementing and extending an Electron app based on TypeScript, React and Node.js to display stream content and technical data
• Extending a Kotlin backend for message processing via Kafka
• Extending various React modules
• Programming custom solutions for customers, including testing
• Creating documentation
• Development in accordance with Scrum processes

Used skills: React, React Hooks, Jest, Vitest, Typescript, Electron, IntelliJ, Vite, Github, Jira, Node.js, yarn, npm, pnpm, Swagger, OpenAPI, Storybook, Docker, Prettier, Eslint, tailwindcss, i18n, GraphQL, CoPilot, Postgres, JSON, Sqlite, trpc, influxdb, Java, Spring, Kotlin, Kafka, Git, Sonarcube

Oracle Project Management and Automation

As part of the project, the operation of an Oracle infrastructure was automated by developing and enhancing Puppet modules and migrating existing Bash scripts to a standardized configuration management solution.

The aim of the project was to standardize and automate administrative processes, improve the maintainability of the Oracle platform, and increase the efficiency and traceability of infrastructure management through the use of Infrastructure as Code.

• Analysis and migration of existing Bash shell scripts to a Puppet-based automation solution
• Development and enhancement of Puppet modules for Oracle environments
• Automation of installation, configuration and operational processes using Infrastructure as Code
• Standardization and optimization of configuration management for Oracle systems
• Creation and maintenance of technical and operational documentation
• Planning, coordination and professional support during project implementation
• Operation and automation of Oracle systems on x86-based Linux server platforms
• Testing and quality assurance of the developed Puppet modules
• Analysis and resolution of technical errors as part of the automation and migration
• Close coordination with specialist departments and infrastructure teams to implement automation requirements

Technologies used: Puppet 7/8, SLES 15, Oracle 19, Oracle Grid, SVN, Windows Server, Confluence, VS Code, Ruby, Bash, Pass

Task:

• Design and build a proof of concept (PoC) for a future-proof virtualization platform, taking secure system architectures into account
• Assess the current state of existing infrastructures and develop selection and evaluation criteria for the right OS virtualization platform
• Carry out the requirements analysis and then create and prioritize tickets in the ticket system
• Complete and continuously update a tool evaluation matrix based on PoC results
• Support team knowledge building through clear documentation of the approach and results in Confluence
• Enterprise analysis of existing hardware (creating different BoMs)

Technologies: Vmware, Vmware Aria Operations, Osism, Canonical OpenStack, FishOs, Linux, Terraform, Ansible, Confluence, Alma

• Designed, built, and launched an internal event planning web application used by over 100 department leads for a large event, despite having no dedicated testing phase.

• Ensured smooth, failure-free operation during first production use, leading to the tool being adopted for future events.

• Automated catering calculations and related workflows, significantly reducing email communication and manual computation effort for meal planning.

• Managed deployment and hosting on a Linux server using Coolify, including application setup and runtime operations.

• Hired and guided a communication designer on UX while independently owning all technical decisions and implementation.

• Further development and operation of a central backend service for providing vehicle inventory for international Mercedes-Benz online shops
• Further development of a reservation service for vehicles as part of the checkout process
• Design and implementation of a highly scalable end-to-end test architecture with a focus on maintainability, reusability, and a high number of automated test cases
• Development of a multi-layer test infrastructure with a strict separation of test logic and access layers
• Development of an initialization and caching architecture to significantly speed up local and CI/CD-based test runs
• Development of an AI-supported review architecture for automated evaluation and quality assurance of end-to-end tests
• Development of a dashboard for consolidated display of a vehicle context across multiple backend systems, including AI-generated summaries and compact case analyses
• Integration and further development of connections to various reservation systems via Apache Kafka and REST
• Design of new microservices and support with architecture decisions
• Risk analysis and design of microservice migrations
• Technologies: Java, Spring, Spring Boot, Gradle, Maven, Apache Kafka, REST, OpenAPI, Swagger, Github, Confluence, CI/CD, Microservices, AI, LLMs

• 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

• New development and further development of frontend interfaces for investors, using HTML5, JavaScript, CSS, React, Material UI, and JSTL

• Created an application to control measurement hardware with a Tauri application using React.JS and TypeScript on Raspberry Pi
• Developed a cloud application for storing and analyzing measurement results using Spring Boot and React.JS
• Built a Tauri application for printing ZPL labels on Windows
• Technologies: Java, JavaScript, Tauri, Rust, React.JS, AWS, Kubernetes, Docker, GitLab CI/CD, REST API (JSON), Maven, CI/CD, PostgreSQL

Cross-brand design system

Focus: Analysis of the causes of recurring layout deviations in design system components. The cause was the integration of visual regression tests (BackstopJS) into the build and approval process: deviations were not blocked, and reference images were replaced without approval.

Recommendations for a controlled workflow with mandatory approval and test results as a prerequisite for merging. Contributed to the successor system based on Lit/Web Components.

Technologies: Lit, Web Components, SCSS, Gulp, BackstopJS, GitHub Enterprise, JFrog Artifactory

• Designed and specified the technical network integration of a new business critical application system (MUREX) in the capital market area in a complex interface and outsourcing environment.

• Created component specifications, catalog of measures and implementation plan.

• Ensured proper integration of developed results in accordance with the bank’s framework: IT compliance, IT security, change and release management.

• Selected and integrated a new service provider for the bank; moved critical bank applications to the provider.

• Designed, implemented and supported the new Cisco network and Fortinet security setup at the service provider data center.

• Acted as technical interface between bank, service providers and consulting partners.

• Supported and further developed the network and security infrastructure (clients, servers, networks); performed error analysis and implemented solutions within agreed service levels.

• Analyzed and diagnosed all security and network failures, glitches and malfunctions.

• Initiated continuous enhancements to guarantee efficient resource utilization and acceptable response times to users.

• Provided network support in financial service organization and operational change preparation on production banking network infrastructure for both large and small projects within strict change management discipline.

• Designed, defined, tested, governed and improved engineering standards.

• Performed role of network architect for medium-large projects involving team resources.

• 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)

• IT training in theory and practice for IT specialists in application development and system integration