Legacy Modernization Experts in Germany

• Consulting, design, analysis, software architecture and development
• Design, development and implementation of a Pimcore environment and connection of several external API systems in a Kubernetes environment, as well as various PIM and ERP systems
• Technologies: Unix environment, design, Symfony development, design, PHP 8+, software architecture, MySQL/SQL, Shell Script, Git Dev Ops tasks, AI coding assistance, Pimcore 12, Shopware 6
• Team size: >10 people

Built an international e-commerce platform for a multi-vendor marketplace for digital assets from scratch. Designed and operated cloud native architectures at enterprise scale.

• Designed and operated a highly scalable microservice and serverless architecture
• Built the complete cloud infrastructure with Terraform + AWS CDK in AWS
• Provisioned ECS/EKS clusters (Fargate), Application Load Balancers (reverse proxy), and Lambda functions
• Observability & tracing with CloudWatch, DataDog, Prometheus, and Grafana
• End-to-end setup with DataDog (formerly AWS CloudWatch), Prometheus, and custom Grafana dashboards
• Integration of advanced metrics (including ORM mapper) and distributed tracing with Jaeger
• Robust backup and disaster recovery strategies
• RDS Postgres backups and hourly snapshots
• Read-only, asynchronously synchronized replicas with automated master failover in emergencies
• Minute-level rollback capability through versioned Docker images on ECS and Git-based CI/CD pipelines
• Created CI/CD pipelines with GitHub Actions for automated multi-stage deployments (Dev, Testing, Prod)
• Integrated Stripe for international payment processing
• Built a marketplace payment system with multiple parties and payout routines
• Used Algolia for high-performance real-time search of digital assets on the platform
• Federation of services with GraphQL and Hasura
• Later migration to GraphQL Mesh
• Test Driven Development (TDD) - unit, integration, and E2E testing with Jest, Vitest, and Playwright
• Used Next.js / React for modern frontend applications in the nx monorepo
• Enterprise security architecture & access control
• Integration of JWT tokens with Auth0, OAuth, OIDC, IP guards, BOLA protection, and secret vaults
• Authorization concepts with RBAC, ABAC, and native Postgres Row-Level Security (RLS)
• Built internal microfrontends with Retool for fast prototyping and operational business processes

Technologies: ABAC, AWS CDK, AWS CloudWatch, AWS ECS, AWS EKS, AWS Fargate, AWS RDS, AWS S3, Algolia, Auth0, DataDog, Docker, GitHub Actions, Grafana, GraphQL, GraphQL Mesh, Hasura, JWT, Jaeger, Java, JavaScript, Jest, Kotlin, Kubernetes, Monorepo, Next.js, OIDC, Playwright, Postgres, Postgres RLS, Prometheus, RBAC, Redis, Retool, Serverless, Stripe, Terraform, TypeScript, Vitest

• 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

• Development of safety-related embedded software for a mobile machine on a Hydac TTC 2390 controller.
• Implementation in C with consideration of SIL 3 / ASIL D and MISRA-C:2025.
• Implementation of communication via CAN, CANopen, and J1939.

Standards, guidelines and norms: ISO 26262, IEC 61508, MISRA-C:2025

Technologies: C99, Hydac TTC 2390, Infineon TriCore Aurix TC397, Hightec C/C++ Compiler, PC-lint Plus, CAN, CANopen, J1939, MISRA-C:2025

Software engineering and integration consulting for enterprise clients, with a focus on backend development, APIs, system integration, and event-driven architectures. Currently developing and evolving a recruitment and staffing platform using Elixir and RabbitMQ, including asynchronous, event-driven communication and integrations with external recruitment and staffing platforms.

Interim Lead ITSM Transformation

Industry: Retail & Industry – Optics (partly critical infrastructure)

Mandate: Transition of ITSM governance to the product- and capability-oriented governance model already established across the Group, as well as acceleration and partial automation of service volumes through optimized entry channels. Design and system-based implementation of an ITSM target operating model.

• ITSM target process design based on the capability owner model: target processes and ownership for Incident, Service Request, Problem, Change Enablement, CMDB, Service Level, Supplier and Knowledge Management, derived from the Group-wide target operating model
• AI-supported Enterprise Service Management: Reorganization of currently mixed requests into a structured, cross-functional service model including a new self-service portal. AI-supported classification and automation considered in the architecture model
• Migration & Cloud Architecture: Planning and management of the end-to-end migration, coordination of cutover management and go-live support; ensuring productive stability during the hypercare phase. Consideration of a multi-source CMDB (~500,000 assets), connection of go-live-critical field service and vendor interfaces
• Scaling & Blueprint: Central instance for headquarters and production, designed as a blueprint for additional international retail and production sites
• Delivery and Stakeholder Management: End-to-end management from target vision to go-live with regard to time, budget & quality. Building consensus and balancing interests between independently managed IT units up to CIO level

Design and implementation of a compact ERP, CRM, accounting, and production-planning platform for a German food manufacturer. The system replaces Rechnung11, self-built Excel sheets, and manual processes for fewer than 10 internal users.

• Designed and implemented the full platform architecture as sole architect and developer.
• Built modules for customer management, B2B order handling, invoicing, production planning, and accounting support.
• Implemented DATEV export, ZUGFeRD/XRechnung e-invoicing, FinTS bank statement synchronization, and GoBD audit trail concepts.
• Used AI-supported workflows for prototyping, test support, and implementation acceleration while retaining full architecture, review, testing strategy, and technical ownership.

Technology: Java 23, Spring Boot 3, Spring Data JPA, Spring Security, Vue 3, TypeScript, PostgreSQL, Flyway, REST, OpenAPI, JWT, TOTP, RBAC, DATEV, FinTS, ZUGFeRD, XRechnung, GoBD, JUnit, Mockito, Testcontainers, Playwright, Docker, GitLab CI/CD

• Developed complex React/TypeScript frontend systems for highly customizable lens products.
• Designed internal tooling for validating and managing product configuration constraints.
• Led accessibility initiatives to align customer-facing applications with EU accessibility requirements.
• Worked extensively in large legacy codebases while incrementally improving maintainability and developer experience.
• Collaborated across multiple teams in an international e-commerce environment.

• Data Engineering: Design and implementation of scalable data pipelines
• Legacy migrations to Microsoft Fabric (Lakehouse, Dataflows Gen2, Pipelines)
• BO Universe migrations to MS Fabric / Semantic Models / Power BI
• Taskforce for data-driven transformation projects involving Azure Fabric / Oracle / MSSQL

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.

Key responsibility for the visual and technical frontend relaunch as well as the continued development of the platform architecture.

• Designed and continuously developed the frontend architecture, including a Figma-based Component Library and migration to Vue 3.
• Developed a robust, high-performance, component-based CSS architecture.
• Continuously optimized accessibility, Core Web Vitals, and web performance.
• Worked closely with UX, Product, and Editorial teams on design, product, and implementation decisions.

RESULT:

• WCAG-compliant
• Core Web Vitals issues resolved
• PageSpeed ~90 Desktop / ~80 Mobile

• Savills is one of the world's leading property advisors with 700+ offices worldwide. In Berlin, I built core digital solutions for the valuation business, replacing legacy Access-based workflows with an enterprise-grade web app built on Vue.js.
• Frontend Architecture & Scalability: Designed scalable Vue + TypeScript frontend architecture for internal enterprise applications, integrating a Symfony backend and interactive maps.
• Legacy Modernization: Led the modernization of legacy jQuery-based systems into maintainable Vue-driven applications, improving performance, maintainability, and efficiency across business workflows.
• PDF Report Workflow Automation: Engineered Twig-based automated PDF generation pipelines that reduced manual report preparation time by ~80%, saving approximately 12h per analyst/month.
• Design System & Frontend: Built a scalable SASS-based design system using mixins, maps, functions, and reusable UI patterns for consistency and long-term maintainability.

Architecture reviews, legacy modernization, system integration, and AI integration into existing systems.

Consulting and prototype work on AI voice and multilingual agent systems, using AI-assisted delivery across realtime translation prototypes, call-centre automation, and voice-to-voice consultation workflows.

• Built and advised on AI voice / agentic conversation prototypes, including realtime translation and consumer-facing consultation experiences.
• Worked across call-centre automation, voice UX, product architecture, implementation tradeoffs, and prototype development.