CSS Experts in Cologne

• Self-hosted table tennis equipment platform.
• Development of a custom “Racket Builder” that uses a co-evolutionary genetic algorithm to identify, evaluate, and recommend the optimal combinations of racket blades and rubbers based on physics heuristics and player data within a search space of over 4 billion combinations.
• Development of a custom fully automated web crawler to capture equipment specifications, integrating an automated pipeline for image normalization as well as data harmonization via DeepSeek.
• Cloudflare Edge Workers written in Rust to perform low-latency data searches and offload computationally intensive simulations from the main server.
• High performance and accessibility standards across a large Nuxt 4 codebase achieving 95–100/100/100 Lighthouse scores.

PLANT-MY-TREE®-per-order

The application enables Shopify merchants to automatically place tree-planting orders for every incoming order. By integrating ecological contributions directly into the purchase process, the manual effort for tracking and billing reforestation initiatives is eliminated. The system increases transparency for end customers through real-time visualizations of the ecological impact directly in the storefront. The architecture is based on a modular monolith with Spring Boot in the backend and an integrated React app inside the Shopify admin area. The solution uses webhooks to capture order data in an event-driven way and integrates the weclapp ERP system for automated monthly invoicing. An app proxy mechanism provides dynamic statistics such as CO2 compensation and planted trees without any performance loss for the merchant shop.

Tasks:

• Design of the modular software architecture based on Spring Modulith to ensure high maintainability
• Development of the event-driven business logic for evaluating Shopify orders via webhooks
• Implementation of automated invoicing by connecting the weclapp REST API
• Building the frontend using React Router and Shopify App Bridge for native integration
• Design of the database model and implementation of the persistence layer with JPA/Hibernate and Prisma
• Integration of internationalization processes for global use in the frontend and email communication
• Automation of deployment processes using Docker and GitLab CI/CD

Project skills: Java 25, Spring Boot, Spring Security, Spring Modulith, Hibernate, JPA, REST API, PostgreSQL, Maven, Liquibase, React, TypeScript, React Router, Vite, Node.js, Prisma, Zod, Docker, Docker Compose, GitLab CI/CD, Shopify CLI, Shopify App Bridge, Polaris, weclapp, i18next, Lombok, Vitest

• Built a modular C++ 20 embedded Linux acquisition system on a Raspberry Pi, synchronizing IMU and dual-camera data streams to sub-millisecond accuracy.
• Integrated retro-reflective and contrast sensors to trigger acquisition and detect gaps between sorter rails.
• Implemented SPI & I2C sensor communication, GPIO interrupt handling with libgpiod, and CSV & JSON output.
• Designed a multi-threaded acquisition pipeline and an SPSC queue between acquisition and writer threads.
• Built a Python/HTML/CSS based web-server and validated the prototype in a DHL warehouse for defect detection.
• Documented software behavior, configuration, and results for maintainable handover and further development.

• Structured analysis and evaluation of business processes

• Gathering, documenting, and prioritizing requirements

• Creating business-friendly and technically executable process models

• Use of Camunda tools

• Deriving requirements and interfaces from BPMN diagrams

• Coordination with stakeholders and business units

• Translating business requirements into technical solution designs

• Implementing efficient and tailored applications

• Systematic collection, analysis, and documentation of requirements

• Prioritizing and validating requirements in close collaboration with stakeholders

• Alignment between business and development to ensure shared objectives

• Creating use cases, user stories, and acceptance criteria

• Continuous requirements and change management throughout the project lifecycle

• Define project goals and create project plans

• Delegate tasks and monitor project progress

• Monitor budgets and inform stakeholders

• Mendix: Architecture, development, and maintenance of custom applications (Microflows, Domain Model, Security, XPath)

• Modeling Mendix workflows for process optimization

• Develop scalable apps with Mendix including REST/SOAP integration with SAP, SQL, Azure & SharePoint

• UI design for Mendix using Atlas UI, Fluent UI, HTML, CSS, JavaScript

• Develop web & mobile apps with Mendix using agile methods (Scrum, Kanban)

• Implement business logic with Mendix Microflows and Nanoflows

• Performance optimization and architecture improvements for Mendix applications

• Conduct Mendix training

• Create technical documentation and best practices for Mendix

• Coaching and mentoring for low-code development with Mendix

• Automation of the database major / minor releases for the TKeasy project

• Concept for database major / minor release automation

• As-is analysis

• Evaluation of Redgate Flyway functionality

• Concept creation

• Products: Redgate Flyway, GitHub, Quest, Erwin Data Modeller, Oracle, Atlassian Jira, Atlassian Confluence

• Skills: Docker, Continuous Delivery, Continuous Integration, Redgate Flyway, Major Releases, Minor Releases

Consulting on and implementation of technical processes in CRM and email marketing, international project management

• Tested integration of TIBCO EBX with SAP S/4HANA via TIBCO BusinessWorks – proof of concept
• Implemented use case: communication between TIBCO EBX and SAP S/4HANA via IDocs to exchange material master data and business partner data
• Customized, configured, and implemented inbound and outbound processing in the SAP S/4HANA environment for communication with the TIBCO EBX software interface
• Distributed classes, characteristics, and values between TIBCO BusinessWorks and SAP S/4HANA and customized the inbound processing
• Documented the technical components

• UI design of the Penny mobile app and ongoing maintenance of the company-wide design system — carried out with a senior UI designer from the Artyspark team.
• Managing, briefing, and quality control of all design decisions; close coordination with Penny's internal product team in product management and development.
• Ensuring consistent UI standards across the app and design system; reviewing and approving components, tokens, and guidelines.

• Network elements, network, operational and operator-related systems
• Supporting around 20 different products (managed agile)
• Requirements analysis and management (functional and non-functional)
• Test concept and planning (scope, test phases, effort, schedule, resources, organization, etc.)
• Aligning approach with clients and service providers
• Managing and assisting in creation of test cases for system, integration and end-to-end tests
• Guiding and supporting test execution
• Defect management and planning bug fixes with external providers
• Preparing and facilitating workshops
• Regular reporting and creating automated test reports
• Further development of agile testing methodology and configuration of supporting tools
• Conceptual support in developing a quality seal for rating product and service quality of internal and external providers
• Requirements engineering based on ISO/IEC 25010, Scrum, SaFE
• BMC Remedy, Atlassian Confluence, Atlassian Jira (including plugins Xray, Structure), Microsoft Office (incl. Visio), Obsidian, doxis document management system, Gitlab, Obsidian

• Independent CPQ consulting for a portfolio of industrial manufacturers, including Scheidt & Bachmann, Trützschler Group SE, and Weiss Klimatechnik GmbH (Schunk Group)
• Full project coverage: requirements analysis, concept, system design, implementation, testing, and international go-live support
• Deep integration work with SAP ECC (material master replication, SD document creation, material creation, general APICONNECT and other web service interfaces)
• Process consulting: analysis and optimization of internal quoting processes for sales and management
• Knowledge transfer/coaching and pair programming to strengthen internal team skills

• Owned the development of partner-critical onboarding processes of the B2B2C-facing SaaS platform.
• Collaborated cross-functionally with engineering, design, and enterprise clients to deliver a scalable and API-first onboarding flow.
• Delivered the company’s main initiative — dynamic product — in close collaboration with internal SMEs and energy supplier clients.
• Increased successful user activations by 10% through streamlined ADDRESS API integration and real-time monitoring tools.
• Defined and prioritized product roadmap based on business goals, client needs, and platform vision.
• Led discovery sessions and co-creation workshops with customers, turning insights into validated product opportunities.

• Assessing the current status (planning stage / rollout status) of the so-called inter-polygon routes
• Creating an end-to-end project plan for the individual routes, considering active and passive components and tasks
• Monitoring and controlling the implementation of the plan
• Optimizing the chosen network architecture
• Creating network and splice diagrams

• Further training to become a certified AI expert in the company
• Fundamentals of AI
• AI tools
• Prompt engineering (creation of professional prompts)
• (Advanced) Process automation with AI and make.com
• AI in marketing and sales
• Legally compliant use of AI in companies
• Intelligent knowledge management
• AI in customer management
• Developing AI guidelines for the company
• AI integration into the company

• Evolved the platform from bare-metal infrastructure with a monolithic PHP application to a hybrid Google Cloud architecture with Go microservices on Kubernetes
• Managed and scaled a production infrastructure with 300+ VMs and dozens of clusters, including MySQL, PostgreSQL, MongoDB, RabbitMQ, Redis and Elasticsearch clusters
• Designed architecture, deployment, monitoring, performance analysis, and upgrades for all platform services using Terraform and Ansible
• Migrated observability systems from ELK and Prometheus to Datadog, managed with Terraform
• Introduced Jenkins CI/CD with SonarQube integration and automated tests to speed up feedback cycles
• Containerized the testing environment and implemented GitLab CI pipelines for Docker image builds, static code analysis, and infrastructure tests
• Performed zero-downtime migrations of MySQL and MongoDB clusters to Google Cloud
• Developed reusable Ansible roles for database clusters and automated data obfuscation for staging environments
• Decomposed monolithic databases and migrated to microservice architectures
• Built tools to detect and optimize slow queries in MySQL and MongoDB
• Conducted online schema migrations with pt-online-schema-change without downtime windows
• Developed internal Go applications for batch queries, GitLab-Jira integration, and MongoDB backup recovery
• Technologies: Debian, Ubuntu, Alpine, Go, Bash, Python, PHP, SQL, GitLab CI, Jenkins, Drone CI, MySQL, MongoDB, PostgreSQL, Redis, Elasticsearch, RabbitMQ, Kafka, Docker, Kubernetes, Nomad, Ansible, Terraform, Grafana, ELK, Prometheus, Datadog, Nagios, Zabbix, Nginx, HAProxy, Vault, Helm, SonarQube, Filebeat, Auditbeat, Google Cloud, AWS