Linux Experts in Dortmund

Development and evolutionary further development of a highly available, cloud-native microservice and integration architecture for dealer and retail processes in the Porsche Car Configurator.

Responsibilities

• Development of Java-/Kotlin-based backend, API, and integration components (Spring Boot)
• Integration of internal and external systems via REST/OpenAPI, GraphQL, Apache Kafka, and AWS SQS (synchronous and asynchronous)
• Implementation of stable, high-performance communication and data flows in a cloud-native platform architecture
• Processing of structured data formats (JSON, Protobuf, GraphQL schemas) based on existing API patterns
• Performance optimization of distributed microservices with reduced response times and higher operational stability
• Technical tests (unit, integration, and API tests) as well as error analysis in production-like environments
• AWS Infrastructure as Code with Terraform and AWS CDK
• CI/CD automation (build, test, and deployment pipelines) with GitHub Actions
• AI-supported feature implementation (GitHub Copilot Agent)

Label: Kotlin, Java 25, Spring Boot 4, Protobuf, TypeScript, AWS, Terraform, CDK, Apache Kafka, AWS SQS, REST/OpenAPI, GraphQL, JSON, PostgreSQL, Docker, GitHub Actions, Maven, Gradle, JUnit, Mockito, Testcontainers

Manufacturing intelligence platform with enterprise workflows, RAG, real-time AI assistant features, and multi-repository backend architecture.

• Built and extended production AI/backend services with Django, DRF, FastAPI, GraphQL, Celery, PostgreSQL, MySQL, Redis, and WebSockets across a modular multi-repository platform.
• Contributed to ARIS V2, a real-time manufacturing AI assistant using LangChain, LangGraph, MCP tool orchestration, planning/execution flows, OpenAI, AWS Bedrock, Qdrant, and Elasticsearch/OpenSearch-backed retrieval.
• Supported rollout expansion from ARIS V1 in 4 of 17 client production plants to ARIS V2 currently active in 13 of 17 plants, increasing real-world deployment coverage to more than 50% of the client footprint.
• Worked on document-grounded RAG functionality including ingestion, OCR, chunking, embeddings, indexing, retrieval, reranking, and grounded answer generation for industrial workflows.

Stack: Python, Django, DRF, FastAPI, LangChain, LangGraph, GraphQL, Celery, WebSockets, OpenAI, AWS Bedrock, Qdrant, Elasticsearch/OpenSearch, PostgreSQL, MySQL, Redis, Docker.

• Complete greenfield rebuild across the whole stack — built AI-native: backend in Go and NestJS, PostgreSQL (CNPG) on K3s with GitOps/Terraform; frontend on Angular 22, zoneless.
• Orchestrated coding agents (e.g. Claude Code, Cursor) across the entire lifecycle — architecture, implementation, testing, reviews, documentation — driven by Specification-Driven Development (SDD).
• “Bruno” — LLM commentator persona backed by RAG and MCP for a personality that stays consistent across all generations (match previews, post-match reports, his own virtual bets).

Angular 22 (zoneless, without Zone.js), Claude Code, Claude Code Skills, CNPG, Cursor, Design Tokens (Spec for Code), Docker, Gherkin, Git, GitLab, GitOps, Go, Google Gemini, Grafana, Hetzner Cloud, K3s, Keycloak, Kubernetes, Lighthouse, LLM Integration, Model Context Protocol (MCP), NestJS, Node.js, NPM, Playwright, PostgreSQL, Prometheus, RAG, REST, Specification-Driven Development (SDD), Structured Outputs, Terraform, TypeScript, Vitest

• Delivered MVP-focused full-stack architecture for a health-sector client: Vite/React frontend, backend services on Google Cloud Run, and Supabase for database plus IAM/authentication.
• Supported product requirements engineering and prioritized cost-aware workload placement, implementing browser-side/edge computation where feasible before moving logic to backend services.

• Architected and deployed end-to-end machine learning pipelines across classification and prediction datasets, ensuring robustness and reproducibility through MLOps best practices.
• Contributed directly to LLM model output accuracy improvement by designing and engineering specialised prompts grounded in end-to-end ML and SciML pipeline logic.
• Developed training data for large language models by formulating coding problems that models could not resolve and subsequently documenting the correct solutions.

• Development of software and system support for RPG development.
• Development, optimization and maintenance of programs in RPG (RPG II to ILE Free Format).
• Performing integration tasks, data management as well as applying and managing system updates.
• User support and training to ensure smooth system operation.

• Optimization of the transmission media of the data links in the Ruhr area
• Configuration/expansion of switches and routers for an autonomous system AS
• Improve the network protocols used Layer 2/3 (OSI model), RSTP, broadcast, etc.
• Laying cables, crimping, antennas, routers, switches
• Maintenance, expansion, selection and prioritization of troubleshooting measures for network monitoring (PRTG, The Dude)
• Organization and new connection of another BGP peering, data center, NGN fiber optic
• VPN IPSec site connections for 6 sites with PFSense, Fritzbox
• Configuration of WLAN devices (Mikrotik, UBNT

Label: TCP/IP, VLAN, BGP, OSPF, MPLS, VPLS, routing protocols, WLAN, EoIP, PPPoE, routing, SNMP, DHCP, DNS, NAT, native IP, VLAN, Ethernet, VoIP., switches and routers from: Nortel, Cisco, MikroTik, UBNT., network management systems: The Dude, PRTG, UISP

• Further development and release support for a white-label ePA component for health insurance companies
• Technologies: Android (Kotlin), Kotlin Multiplatform, Coroutines, Jetpack Compose, MVVM, StateFlow, Gradle, ProGuard

Carve-out project: Development of certification strategy, implementation and requirement plans across multiple standards — ISO/IEC 27001, ISO 9001, ISO 14001, ISO 22301, ISO/IEC 20000-1, BSI IT-Grundschutz, and BSI TR-RESISCAN

• Cross-standard inventory and risk assessment
• Coordination with cross-department stakeholders: ISB, executive management, certification bodies, legal and data protection
• Consulting in information security, GRC, and IT auditing

• Presentations and workshops regarding different VOIP products and technologies
• Design of VOIP and network solutions from core to premium solutions and necessary non-standard solutions
• Processing of tenders
• Development of VOIP and network technical implementation of customer requirements
• Implement and configure different UC products on cloud

• Expansion and support of the product portfolio for video analytics and computer vision
• Requirements gathering and engineering
• Consulting, project management and coordination of the pilot and international rollout
• Tools: IP-based camera and video systems, Citrix administration, OneNote, Microsoft Teams, Node-RED, Office 365, Age Verification, Qognify Umbrella, ThingsBoard, Xovis 3D sensors, AXIS cameras, GK checkout software, Atlassian JIRA

• SD-WAN solution by Aruba – Swiss energy company (330 sites): design and implementation of an SD-WAN branch solution with Aruba 9004 gateways, encrypted overlay, policy-based routing, WAN load balancing, and centralized management via Aruba Central.
• LAN/WLAN & security – schools in Germany (9 sites): deployment of Aruba switches & AP-505, FortiGate 80F firewalls; setup of Checkmk monitoring, incident and change management, and secure admin access (BeyondTrust).
• Multi-site security – energy billing company (20 sites): deployment of a complete Fortinet solution (FortiGate HA cluster, FortiSwitch PoE, FortiAP), IPsec remote-access VPN via FortiClient, centralized management via FortiCloud, IntraID authentication, operations and incident management.
• Data center migration – German client: migration of data center switches (Mellanox), firewall cluster, and OfficeConnect switches to a new data center; securing configurations, implementing HA designs, testing, monitoring, and coordinated change and incident processes. Setup of two new 6300 M VSX clustered switches.
• Data center security – university hospital: implementation of a high-availability FortiGate 400F firewall cluster across three data centers; security policy design, operational support, and change/incident management.
• Enterprise campus & network access control – manufacturing company in Germany: introduction of Aruba ClearPass NAC, setup of a VSX-based switching architecture, secure WLAN access with MPSK, and integration into existing networks.
• EU client (Germany & Poland) – Sophos firewalls: operations, incident and change management of Sophos firewalls including IPsec VPN; troubleshooting and ongoing optimization of security configurations.
• Network modernization – pharmacy client in Germany: design and rollout of core and access switching (Mellanox, Aruba Instant On), migration from Sophos to Fortinet firewalls, network segmentation, and security hardening.

• Plan and design complex production systems as part of a team
• Develop and modify electrical circuit diagrams
• Design electrical machine controls and drive technology
• Troubleshoot electronic assemblies
• Develop PLC and visualization software as well as process control software
• Identify and implement optimization measures
• Create operating instructions
• Ensure IT security of all operational technology
• Support building services
• Technologies: Eplan P8, PCS7, ProLeiT, PlantiT, TIA, S7

• Various small consultations, e.g. concepts and arcitectures.
• Updating my Matlab, Linux, IPv6, Cyber-Security, C++ (up to 23) and Python skills.