Software Developer in Cologne

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.

• Backend WordPress web development.

• SPA for automated communication of medical findings with role-based access (Sanctum)
• Server-side LLM integration (OpenRouter) with structured processing
• Automated sending via SMS/voice call (Twilio, ElevenLabs) with queue + status retry
• Full test coverage with 80+ documented test cases

Technologies: PHP, Laravel, LLM API (OpenRouter), Twilio, ElevenLabs, Laravel Sanctum, PHPUnit, Playwright, Docker, REST

• Built more than 15 frontend applications and more than 10 backend services across internal tools, back-office workflows, and external portals for installers and end customers
• Automate build and release workflows with TypeScript and Azure DevOps
• Mentor junior engineers through code reviews and technical guidance
• Integrate AI-assisted and agentic development practices into engineering workflows
• Coordinate user experience decisions with UX designers

Tech Stack: Claude Code, Codex, AWS (S3, Lambda, AppSync, Resolver), Next.js App Router, ReactJS, NuxtJS, Vue.js, Storybook, JavaScript, TypeScript, GraphQL, Azure DevOps

• working in a team using an agile method (Scrum)
• Backend development in Java (Spring Boot)
• Frontend development in Angular

• 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.

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

• 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.

• Develop powerful add-ons for customer service systems with innovative Zendesk apps designed to drive business growth, improve efficiency, and enhance customer satisfaction
• Implement full Zendesk solutions and provide hands-on support to bring customer service vision to life
• Combine customer service and technology expertise to address the complexities of delivering top-notch customer service
• Execute Zendesk implementations in 20+ countries and develop AI apps that automate replies
• Maintain a proven track record of success in advancing customer service capabilities

• Web development with Blazor
• Two-factor authentication for Blazor applications
• Uploading and downloading files
• Bug fixes for existing applications
• Programming interfaces
• Integration of third-party tools and technologies
• Creation of developer tests (unit tests)

• Developed a shop website
• Integrated an AI language model
• Developed tools for AI-powered webhooks
• Technical tools: REACT.js; Elevenlabs; MCP; n8n; HTTP

• Developed a SCIM-compliant Python interface to connect external systems
• Expanded and enhanced UCS modules in Python
• Extended and newly developed Helm charts for container orchestration in Kubernetes
• Maintained and further developed CI/CD pipelines in GitLab
• Implemented automated tests with Pytest and Playwright

'Nubus' is based on a microservice architecture, relies on open source technologies, and runs in Docker containers.

UCS is an IAM complete solution based on Debian, used as an alternative to Microsoft's Active Directory. The work was characterized by the close integration of infrastructure and application logic.

• PHP 8.4
• Platform for prize draws: API-first approach with Symfony/API Platform
• API Platform 4.2 (REST, JWT, Doctrine/PostgreSQL, API documentation) plus AWS tools
• Symfony 7.3 for infrastructure, hosting, and subsequent operation on AWS with ECS
• Postgres
• AWS RDS, SQS, Fargate, RDS Postgres database, and AWS-SQS message queue
• Infrastructure management with Terraform
• After successful Terraform implementation, the next organizational step is to establish a GmbH

• Further development of the existing e-commerce platform based on SAP Commerce (Hybris) to meet the growing demands of digital commerce.
• Ensuring the scalability and performance of the backend, so the platform remained stable and efficient even under heavy user load.
• Development and integration of new OCC REST APIs and services for modular extensions and flexible adjustments, to implement new features quickly.
• Optimization of data flows and interfaces, which significantly improved platform efficiency and system performance.
• Ensuring a maintainable and scalable code base by using Clean Code principles, proven design patterns, and a future-proof architecture.
• Reduction of errors through extensive testing with JUnit, Mockito, and load tests with Gatling, supported by the introduction of automated test processes.
• Improved system performance through targeted refactoring measures and efficient database queries, especially to handle peak loads.
• Use of modern cloud and monitoring tools such as Kubernetes, Google Cloud Platform (GCP), and Grafana to ensure a stable and monitored infrastructure.
• Clear improvement in efficiency, scalability, and reliability of the platform, which now meets the demands of a dynamic and growing e-commerce market.