Cron Experts in Germany

• Co-own the architecture and development of enterprise-grade AI and backend systems spanning communication automation, embedding-based candidate matching and talent-pooling workflows; shape product and feature direction across business, compliance and technical implementation.
• Design and implement production-grade AI pipelines and multi-step LLM workflows, including orchestration, prompt and context engineering, LLM routing and assessment, and integration with internal services and business data.
• Co-own the core candidate-matching system, leveraging vector embeddings and cosine similarity within internal ingestion and attribute-derivation pipelines.
• Drive the architecture and evolution of the candidate-pooling system, including its LLM-based routing and assessment layer.

Built charts for historical data, alarms, and downtime, plus enhanced interactive tables to efficiently track and compare oil-well performance. Eliminated 80% of high/medium security risks (Checkmarx) for the app. Optimized charting libraries, cutting usage from to 300–400MB for large data sets.

Main project lead and consultant for the ePPDS rollout

• Role: Lead consultant for the ePPDS rollout, main project lead for the ePPDS rollout
• Project content: 4) Carried out the pre-project for selecting the detailed planning tool 5) Project planning and team staffing for the ePPDS rollout 6) Solution architect for the digital process landscape around digital production

Technologies: Consulting, project management, customizing

• Responsible for the entire software architecture of the parental allowance portal
• iOS and Android app with React Native and Expo, incl. push and OTA updates
• Store releases via App Store Connect and Google Play Console
• TypeScript monorepo for app, website and backend, web with Next.js and Tailwind
• Own promo, voucher and discount engine with contact and segment logic
• Payments via RevenueCat and in-app purchases, authentication with BetterAuth
• REST APIs based on OpenAPI, PostgreSQL with Prisma and Drizzle
• Self-hosting on Hetzner with Docker, Coolify, Terraform and GitHub Actions
• Tests with Vitest, Playwright and visual regression via Chromatic
• Observability via Grafana Cloud and error tracking with Sentry
• Performance marketing via Meta Ads, measured with custom event tracking
• Grew the product to 20,000 app users with a purchase rate of almost 12 %
• Managing Director since 04.2025, responsible for product and technology

• Further development and maintenance of a complex sales platform with a focus on digital closing processes, customer portal interactions, and document generation for financial and insurance products
• Development and maintenance of microservices with Spring Boot 3 and Kotlin
• Frontend development with Angular 20 for displaying products, applications, and documents
• Execution of end-to-end tests with Playwright and integration tests with WireMock
• Creation and optimization of Quartz jobs and CronJobs
• Refactoring of the security configuration in a multi-realm Keycloak setup with a custom filter chain, permission evaluator, and factory routing
• Creation of dynamic emails with Thymeleaf
• Extensive error analysis with Application Insights, Log Analytics, and direct SQL debugging
• Introduction of a dynamically controlled security architecture with flexible token handling depending on path and realm
• Stabilization and clear structuring of the closing process for complex product models
• Significantly improved maintainability and readability of the code through modular refactorings
• Higher test stability and depth through combined use of Playwright, WireMock, and integration tests
• Targeted performance optimization through analysis of Hibernate statistics, query tuning, and use of SQL execution plans
• Technologies used: Java 21, Kotlin, Spring Boot 3, Angular, TypeScript, REST API, JSON, Kubernetes, Docker, PostgreSQL, Liquibase, Keycloak, OAuth2, GitHub Actions, Testcontainers, Azure Application Insights, Thymeleaf, Tilt, Microsoft SQL Server

• 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.

• Planned and implemented new network infrastructure (VLAN, LACP, DMZ, structured cabling)
• Migrated from VMware to KVM using Oracle Linux Virtualization Manager (OLVM), including CPU pinning
• Hardened the entire environment using SELinux (KVM hosts, container hosts, database servers)
• Configured and operated the virtualization platform with OLVM and Ansible-based provisioning
• Containerized and redeployed critical services: WordPress, Jenkins, PostgreSQL, MariaDB, Subversion with Apache + AD integration
• Developed Ansible playbooks for automated deployment and configuration management
• Integrated Foreman for repository and security management in the DMZ
• Produced technical documentation in Markdown; organized in Bookstack
• Coordinated with external vendors (e.g. HPE) for hardware installation and setup
• Delivered all contributions documented and reproducible in Markdown

• Designed and provisioned full AWS infrastructure using Terraform, implementing containerized solutions with Docker Swarm and Kubernetes for scalability and reliability.
• Built multi-environment CI/CD pipelines (Prod, Staging, Test) using Jenkins, GitLab CI, and Maven for automated builds, tests, and deployments.
• Configured secure networking with VPCs, subnets, security groups, NAT gateways, and routing for high availability.
• Integrated Prometheus, Alert Manager, and Grafana for real-time monitoring and proactive incident response.
• Orchestrated deployment of microservices with Helm, ensuring zero-downtime releases and fast rollback capabilities.
• Mentored junior DevOps engineers on best practices in IaC, Terraform, AWS security, and container management.

• Technical lead of a team developing agentic chatbot solutions (React, TypeScript, Python, FastAPI)
• Architecture design for multi-LLM dialog systems - focus on maintainability, UX, and autonomous execution
• Stakeholder alignment, CI/CD processes, and AI integration at enterprise level

• Built a WebSocket progressive streaming pipeline replacing 15+ second blocking fetches with near real time updates.
• Deployed Nginx with HLS/RTMP for live and on-demand video: reliability up 35%, latency down 30%, concurrency up 45%, bandwidth down 20%.
• Added client-side caching with AWS S3 pre-signed URLs; image loads dropped from about 5,000 ms to under 20 ms, boosting page responsiveness.
• Optimized video frame annotation pipeline by introducing Python threading to parallelize S3 uploads, reducing processing time by ~40%.

• Overhaul of the entire design and implementation of new UI/UX aspects using React
• Planning of the software architecture and structuring of the project for long-term scalability using Git for version control

• Planning and implementing the upgrade of the existing TYPO3 installation to TYPO3 11, including switching to a Composer setup (Composer-based deployment)
• Migrating the underlying MySQL database

• Design of a new cloud service
• Requirements Engineering
• API Design (REST API, Kafka)
• Consulting on architecture, feasibility and effort estimation
• Implementation of a microservice architecture
• Implementation of a Spring Boot web service
• Development of REST APIs including business and persistence logic
• Kafka consumers and producers
• Various Excel upload/download scenarios
• Change Data Capture
• Cloud provisioning with IaC/Terraform
• Go-live with 30,000 users
• Operation, support and bug fixing for other services

Environment/tools: GitLab, JIRA, Confluence, IntelliJ, Spring Boot, Java, Docker, Terraform, AWS ECS, Postgres, Apache Kafka, SAP Datasphere, JUnit, Debezium, Apache POI, Hibernate, JPA, Testcontainers

• Backend development of B2B e-commerce solution using SAP Commerce Cloud, leveraging Java and Spring Framework with creation of REST APIs for effective communication.
• Resolved software defects, developed automated cron jobs and triggers, and authored unit tests with JUnit to uphold code stability and quality standards.
• Utilized Git-based version control systems (Bitbucket/GitHub) for source code management and used Jenkins to support continuous integration and development (CI/CD).
• Executed and closed multiple user stories and tickets across iterative bi-weekly sprints under Agile (SCRUM) methodology.
• Led incident resolution in the production environment and minimized downtime through real-time monitoring (Solr, SAP CCv2, OpenSearch Dashboards) and sustaining SLA targets above 99%.