JavaScript Experts in Cologne

• Coordination and planning, execution, documentation, and analysis of test cases
• Development of test concepts considering best practices (e.g., test pyramid) with a focus on reliable, automatable test runs
• Implementation and maintenance of test cases according to the test concepts
• Technologies: Citrix Workspace, Shopify, Jira, Xray, MS Teams, MS SharePoint, Confluence, MS Office 365

• 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.

• 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

• Supporting the DevOps team in Terraform-managed, multi-region AWS infrastructure to achieve environment parity.
• Developed end-to-end CI/CD pipelines using AWS CodePipeline, CodeBuild, and CodeDeploy, automating the build and deployment.
• Maintained pre- and post-deployment scripts to automate critical tasks such as database schema migrations and environment sanity checks.
• Implemented CI/CD flow specifically for hotfixes via separate Git branches, managing back-merge activities from feature branches to release branches to ensure code integrity through automated conflict resolution.
• Deployed a dedicated, lightweight sanity check application hosted cost-effectively on Azure Container Apps to run automated health and basic functional checks as a post-deployment activity triggered via pipeline.
• Investigated production incidents through code changes and AWS CloudWatch logs.
• Coordinated integration of Dynatrace APM and its APIs for monitoring purposes.
• Full stack QA strategist for a high-traffic e-commerce platform built on a layered architecture for the back-end testing of core platform services, especially the order management system in Zed and Glue layers.
• Managed automation activities, testing process, and refactoring practices.
• Responsible for framework migrations, setup, and training for new automation frameworks.
• Promoted a shift-left approach within the QA team and created the test concept.
• Participated in meetings with IT managers, business owners, product owners, and team members.
• Designed and implemented contract testing to validate API schema compatibility between the order management system and the Zed and Glue layers, reducing production-relevant breaking changes by approximately 3%.
• Led the migration to a multi-environment framework that enabled test execution across 4 country configurations from a single codebase.
• Integrated automated unit and functional tests directly into the GitLab CI/CD pipeline, reducing pipeline runtime by 32%.
• Coached and trained 5 QA engineers across Germany and Hungary in test automation, framework architecture, and best practices.
• Architected a layered backend test automation framework separating business logic, API request builders, and the database layer.
• Piloted AI-assisted testing with Playwright Agents, the Playwright MCP Server, and GitHub Copilot for automated test generation, execution, and self-healing Playwright scripts.

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

• 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

• Building an AI-native coaching platform for cyclists: a conversational Dynamic Coach that turns training and recovery data into the next session decision, available daily instead of a static calendar.

• Designed and shipped a full-stack, chat-first coaching experience on Next.js and the Vercel Edge Network, with agentic workflows that adapt plans in real time to readiness, load, and life constraints.

• Built integrations with Garmin, Strava, Whoop, and intervals.icu so sleep, HRV, and ride data feed coaching recommendations without manual data entry.

• Product thesis: make high-quality coaching principles accessible at scale by combining adaptive training logic with plain-language conversation, not another metrics dashboard.

Industry: digital sovereignty, public sector

Responsibilities:

• Project coordination (teams: consulting, development, testing, deployment/operations)

Products and standards:

• Jira, Confluence, Asana, Miro, Mural
• Open Source, Keycloak, Open Xchange, ownCloud

• AI-assisted creation of test cases and test data
• Creation of test cases based on requirements
• Execution of manual tests
• Defect documentation, retesting and tracking

Technologies & Tools: SCRUM, Jira, Confluence, Zephyr Scale

Project: Digitalization of Warehouse Processes | Building a Data Analytics Platform.

• Built a web-based workforce allocation system that digitized daily shift planning by matching worker expertise to operational zones, replacing manual coordination with a structured workflow adopted across the site, saving supervisors time on daily planning.
• Developed a real-time operational visibility dashboard giving supervisors a live view of task throughput and outstanding workload across warehouse zones throughout the day, helping reduce overtime and idle labour costs.
• Developed a slotting optimization solution to improve warehouse picking efficiency and reduce picking time per order, working directly with operations teams from concept through production deployment.

Technologies used: Python, Django, PostgreSQL, Pandas, NumPy, HTML, Java, JavaScript, Docker, Kubernetes, AWS, Power BI, GitHub Actions CI/CD, GitOps, Claude, OpenAI

• 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

• Delivered ML pipelines for OCR, semantic search, and computer vision
• Integrated Azure AI Agents and GPT workflows for automation and QA
• Deployed cloud-based FastAPI services with scalable architecture
• Created integration docs and advised on LLM production readiness

• Backend WordPress web development.

• Led the end-to-end architecture and migration of a legacy on- premise IoT monitoring system to a cloud-native Azure platform within a 17-member development team
• Designed and implemented a scalable microservices architecture (Java 21, Spring Boot, Kubernetes, Azure Services), decoupling IoT data streams and eliminating legacy system bottlenecks
• Defined technology stack, mentored developers, and orchestrated cross-functional teams in 4 countries to ensure high-quality delivery and alignment with architectural standards
• Drove requirements engineering and system redesign, removing years of technical debt and introducing event-driven processing and automated workflows
• Key Achievements
• Increased system stability and uptime by ~10x, eliminating need for 24/7 DevOps intervention
• Reduced hosting costs by ~80% (5x savings) through cloud optimization
• Improved performance and scalability, enabling stable handling of high-volume IoT data streams
• Delivered successful zero-disruption migration from on-prem to cloud, with strong user satisfaction and reliability from day one