Linux Experts in Stuttgart

• Situation: Increasing demand for privacy-compliant AI solutions for clients in the KRITIS and mid-market sector that need to analyze sensitive media content (audio, video, documents) without sending data to public cloud LLMs.

• Task: Design, deployment, and secure operation of a fully self-hosted AI infrastructure including a custom-built digital management platform for automated media analysis.

• Action: Architected and implemented a multi-tier platform on hardened Proxmox infrastructure with frontend (Nuxt 3, Vue 3, TypeScript, Tailwind 4), backend (Laravel 13, PHP 8.4, Sanctum), data storage (PostgreSQL 16, MongoDB 7), caching/queuing (Redis 7, Laravel Queue), AI workers (Python 3.11, Whisper, DeepFace, Librosa), scheduling (Laravel Scheduler/Cron), and local LLMs (Gemma, DeepSeek, Qwen, Mistral, LLaMA, Phi) via OpenWebUI with segmented network access, API hardening, and audit logging following BSI recommendations.

• Result: Fully GDPR-compliant, on-premises AI platform with zero data leakage to third parties.

• Task: Overall responsibility as an external Head of Cyber Security / CISO-as-a-Service for the design, implementation, and continuous improvement of ISMS according to ISO 27001, BSI IT-Grundschutz, and NIS2.

• Action: Built and managed Cyber Defense Centers (CDC) with SOC operations, integrated SIEM solutions (Splunk, Graylog), established risk-based vulnerability management (Qualys, Nessus, OpenVAS), and conducted regular infrastructure, application, and physical penetration tests.

• Result: Audit-ready ISMS for multiple clients and a 60% reduction in critical vulnerabilities within 90 days.

• Task: Design and execution of NIS2 assessments and operational roll-out plans for KRITIS operators.

• Action: Developed an online assessment tool for automated identification of individual weakness profiles, implemented ISMS optimizations, penetration testing, awareness programs, GRC suite deployment, and delivered C-level presentations.

• Result: Accelerated the consulting process by 50% and successfully prepared multiple clients for NIS2 compliance.

• Task: Incident commander for crisis response, forensics, and business recovery in ransomware attacks and APT campaigns.

• Action: Coordinated with state and federal police (LKA, BKA), performed forensic analysis (OSForensics, Wireshark, Kali Linux), executed disaster recovery and BCM strategies, and developed BTC extortion response strategies.

• Result: 100% recovery rate within defined RTO windows and sustainable post-incident security architectures.

• Action: Planned, built, and operated a hardened multi-VM infrastructure (Proxmox, 15+ VMs) with web and mail servers, Graylog, OPNsense firewalls, CRM/ERP and LLM instances, network segmentation, DDoS mitigation, automated patch management, and backup strategies.

• Result: >99.5% uptime over 20+ years and zero compromises.

• Action: Designed coordinated phishing campaigns with five levels of difficulty, developed e-trainings and webinars in a PDCA cycle, and led red and blue teams.

• Result: Phishing click rate reduced from 35% to under 5% within three campaign cycles.

• Development and introduction of operational processes
• Preparation of complete documentation packages (including emergency management and operations) to meet compliance requirements
• Introduction of a workshop on IaC (Infrastructure as Code)
• Professional consulting for the project's security concept (ISMS)
• Installation and operation of Kubernetes clusters on AWS, on-prem, and Azure
• Design of hybrid cloud architecture (on-prem, Hetzner, AWS)
• Analysis and resolution of incidents and system outages
• Network changes to firewall rules, gateways, OpenVPN settings, and IPsec tunnel (pfSense)
• Professional consulting on BitBucket, Jenkins, and GitLab CI/CD pipelines
• Consulting on Ansible deployments and infrastructure automation
• Consulting on building a scalable system in the cloud (AWS / Azure)
• Technologies / Tools: Ansible, Terraform, AWS, Azure, VPN, pfSense, Jenkins, Bitbucket, Kubernetes, GitLab Runner, ISMS, Golang, Prometheus, Grafana, S3, Lambda, RDS, ECS, Cognito, OIDC, Harbor, MinIO, Postgres, Redis, Keycloak, Ceph, Proxmox, CloudFormation, PostgreSQL, Flux CD, Hetzner, IONOS, Sonatype Nexus Repository, Entra ID, Dex IdP, Pulumi

Designed and developed an AI-powered automation platform using n8n to analyze social media niches, identify target audiences, and automate marketing strategy generation. The solution combined AI agents, workflow orchestration, and data analysis to automate research processes and generate data-driven insights.

• Designed and implemented complex automation workflows using n8n
• Developed AI-powered analysis agents for market and audience research
• Integrated multiple APIs and AI services into automated workflows
• Built automated market, competitor, and target audience analysis pipelines
• Leveraged Large Language Models (LLMs) for information summarization, classification, and prioritization
• Containerized and deployed the platform using Docker

Technologies: n8n, AI Agents, OpenAI APIs, Prompt Engineering, LLMs, Docker, Linux, REST APIs, Webhooks

• IT Senior Consultant (bank infrastructure, Active Directory, Azure, security, PKI)
• Planning, design, and implementation of cloud solutions based on Microsoft Azure / M365
• Teams, M365, and cloud services
• Vulnerabilities, threats, attacks
• Security analysis, security policy, security architecture
• Conducting meetings and presentations at various management levels
• Organizing and leading team meetings to improve internal communication
• Tools: PowerShell, Active Directory, GPO, DNS, DHCP, scripting

• Development of a SaaS platform for esports teams with roles, scheduling, statistics, and billing
• Planning and implementation of the architecture, external API integrations, and operations
• Stack: Laravel 13, React 19, TypeScript, PostgreSQL, Redis, and Stripe

• System administration of FreeBSD 11, 12 and 13.1 in a secure cloud software solution
• Administration of proxy servers for FITS and its clients, banks and state banks
• Administration of secure internet solutions
• Administration of secure mail solutions and mail gateways
• Administration of Apache 2.4 web servers
• Planning and maintenance of servers and network components in FNT Command
• Incident, change and ticket handling, especially troubleshooting network issues using Splunk and ARS
• Troubleshooting and log file analysis using Splunk Enterprise
• Monitoring with Nagios
• Ordering, provisioning and installation of certificates on Apache web servers, Nginx web servers and load balancers
• Hardware: HP ProLiant DL380 Gen 9 and 10, Cisco Catalyst
• Software: FreeBSD 11, 12 and 13.2, FNT Command, shell scripts, MySQL databases, ServiceNow, ARS, Splunk Enterprise 8.15

• Support of test management and consulting on replacing the existing core system for non-life insurance with a modern IT platform.

• Planning and controlling test execution as well as test analysis.

• Documentation of test results in JIRA/XRAY and defect management.

• Creating and continuously updating checklists to ensure quality.

• Creating Confluence pages to support test execution and its documentation.

• Creating test completion reports after each test cycle.

• Methods: process planning, status tracking, process optimization, process execution, process quality assurance.

• Tools: MS Office, Outlook, JIRA, Confluence, Wiki.

• Benefit: Support for test management in the preparation, execution and documentation of the different test cycles.

• Consulting, design, analysis, software architecture and development
• Designing, developing, and implementing a Pimcore environment and connecting multiple external API systems in a Kubernetes environment, as well as various PIM and ERP systems
• Technologies: Unix environment, design, Symfony development, PHP 8+, software architecture, MySQL/SQL, shell scripting, Git DevOps tasks, AI coding support, Pimcore 12, Shopware 6
• Team size: >10 people

• Implementing applications with Kotlin and Ktor as microservices
• Using MongoDB in the MongoDB Atlas cloud
• Asynchronous communication of services via Google Pub/Sub
• Using Kotest and MockK for unit tests
• Developing an administration frontend with TypeScript, React and Express.js
• Provisioning environments in GCP using Terraform
• Implementing CI/CD processes with GitHub Actions
• Operating scalable production and test environments in GCP with Kubernetes, Helm and Flux CD
• Monitoring environments with Prometheus and Grafana
• Providing BI data in the Google BigQuery data warehouse

• Investigating the PoC and replacing and refining an existing cloud and IoT power plant control solution for certificate management of renewable energy plants (solar, wind, biomass, etc.) for the largest European renewable energy network operator, including examining the field IoT devices and their integration and network connections, aiming for automated PKI key management.
• Messaging with Kubernetes for large API-connected enterprise applications
• Risk and attack vector analysis, software quality & bug assessments
• Agile workload scheduling via Jira & Confluence
• Evaluation of pub/sub message streams for MQ and Kafka.
• Various tests with “best design approaches” for resilience patterns like circuit breaker designs, throughput measurement and monitoring, bulkhead governors – for robust EA design
• Integration of API management with IBM's API Connect to Kubernetes for platform-agnostic microservices API management designs. Google Apigee
• Solution health check approaches for load burst situations + remedy
• Research and evaluation of potential sub-service providers in the coordinating role as solution manager. CIS20 controls.
• DREAD and STRIDE security assessments.

• Development of a microservice application for calculating postings on accounts

• Development of backend components with Java or JEE, Quarkus, Kafka, Rest API

• Development of the test component with mocking frameworks (Mockito)

• Development of integration test components

• Creation of OpenAPI specification format

• Configuration of CI/CD pipeline

• Development of frontend components with React

• Design, further development and optimization of system structures

• Code review

• Java Corretto 21, JEE, Quarkus, Golang

• Reactive programming with Spring WebFlux, Project Reactor

• Git, Azure DevOps for CI/CD pipeline, YAML, Json Swagger UI, Postman, Rest OpenAPI, Kafka Streams, Kafka Connect, Log4J

• Microservices, Jira, Confluence, MySQL, Docker, Kubernetes (deployment via Helm charts)

• Spring Security, OAuth 2, JWT, Sonarqube

• IntelliJ, Maven, logging framework Splunk, Agile method Scrum, Nexus, Vaadin V24, build tool Vite

• React, React.JS, Node.js, Jess/JavaScript, Tailwind CSS, Agile method Scrum, accessibility BITV, Playwright

• Due to an organizational restructuring towards product-based teams, the implementation of a Data Mesh in the area of Digital Supplier Management (DSM) was decided.
• A highly available real-time Data Mesh for providing large volumes of data via Kafka and REST to other products.
• New development of a core supplier management software in a (micro-)service-based architecture with a modern tech stack.
• Technologies/Tools:
• Java 21
• Spring Boot
• Angular
• TypeScript
• Go
• MapR
• Kafka
• Docker
• Google Cloud Platform (GCP)
• Kubernetes
• Helm
• GitLab CI
• Maven
• JUnit
• Mockito
• WireMock
• Cypress
• Keycloak
• OAuth 2.0 & OpenID Connect
• Humio
• Nexus
• Artifactory
• SonarQube
• Renovate
• Git
• Postman
• IntelliJ

• Product owner and Executive Sponsor for AI Assistant trained on a knowledge base of past solution designs, RFP documents, and current product documentation
• Used by close to 100 global architects and engineers in pre-sales and post-sales
• Generates full solution documents with requirement driven architecture decisions, solution overview, diagrams, bill of material, roles and responsibility matrix
• Technologies: AI, LLM, Chat Bot, RAG, Agentic AI, Vector Databases, Public Cloud

• Led 14 member dev team and delivered postgresql database integration and performance optimization
• Delivered 8 K lines of C code with fewer defects (5 medium to low) in 8 months of development
• Integrate open source pgVector for AI application of the database for exact and nearest neighbor search