TypeScript Experts in Dusseldorf

Gronic Ident & Sign

Core technologies: Android, Jetpack Compose, Retrofit, Regula Document Reader, Adobe Sign

Android app on dedicated devices for identifications and electronic signatures at the PoS

• Training AI models, evaluating images and text UI/UX, turning the provided data into insights through OpenAI Feather as part of the machine learning workflow

Technologies: OpenAI Feather

Volunteer helper at the Johanniter in medical services and disaster response, highlighting teamwork and coordination even in times of crisis.

• Analysis and remediation of security vulnerabilities in a risk assessment system for energy trading
• System analysis
• Threat modeling
• Decision-making on vulnerability mitigation strategies
• Implementation of vulnerability detection mechanisms
• Security scans
• DevSecOps practices
• Technical environment: Visual Studio Code, JetBrains Suite, MS Threat Modeling Tool, DevSecOps, Git, AWS, DynamoDB, SQL Server, Endur, Snowflake, Orca
• Languages: C#, JavaScript, TypeScript, Python, PowerShell, Bash, Terraform, SQL

• Architected and deployed a live B2B geocoding and demographic-data platform for Germany, combining address lookup with census-based population statistics through a web application and REST API.

• Supporting several agile teams in the new product development of an enterprise CRM and ERP application
• Web frontend development with Angular 17–21 (microfrontends, Domain-Driven Design, MDB-Bootstrap)
• Backend development with C# and .NET 7–10, MongoDB, MassTransit, RabbitMQ, Entity Framework Core, ElasticSearch (microservices, DDD)
• Technical feature design for assigned tasks
• Technical architecture design including forward-looking planning of AI-supported extension options
• Proof-of-concept implementation of AI-supported workflows with n8n and a locally hosted LLM (Ollama)
• Coordination with stakeholders and Product Owners, support with sprint planning

Result: Delivery of production-ready microservices and frontend modules in agile sprint cycles.

Environment: .NET 7–10 · Angular 17–21 · C# · TypeScript · OpenAPI · Microfrontends · DDD · Kubernetes · Docker · Helm · MS SQL Server · PostgreSQL · MongoDB · MassTransit · RabbitMQ · EF Core · ElasticSearch · Kibana · Azure DevOps · KeyCloak · n8n · Ollama

• Contributed to the development of an advanced RAG AI Chat application that integrates multiple LLM models, enabling users to seamlessly switch between models based on specific tasks. This improved the user experience by providing tailored, efficient solutions for various use cases, such as event scheduling, booking systems, and complex task management.
• Participated in designing and implementing a robust backend architecture using Spring AI, enabling advanced AI-driven capabilities like intelligent task automation, language processing, and contextual recommendations. Leveraged Spring AI Tools and Advisors to enhance the performance and decision-making of the AI models.
• Collaborated on the integration of vector databases to support embeddings, enhancing the app's ability to understand user queries and perform actions based on complex, real-time data inputs.
• Contributed to the development of a seamless, user-friendly front-end interface using React with TypeScript support, ensuring a modern, responsive, and scalable user experience across platforms.
• Assisted in implementing state management with Redux RTK for efficient data flow and real-time updates, optimizing the overall user experience in dynamic scenarios such as scheduling and task management.
• Partnered with stakeholders to define feature requirements, helping ensure that the app could scale to meet evolving business needs and integrate with other systems like calendar and email services. Worked alongside cross-functional teams, including data scientists and UI/UX designers, to fine-tune AI models and ensure alignment with project goals.
• Contributed to ensuring end-to-end system performance, security, and compliance by helping integrate authentication mechanisms, role-based access control, and secure communication protocols in both backend and frontend layers.

Technology Stack and Key Contributions:

• Java / Spring Boot / Spring AI: Developed backend services leveraging Spring AI for intelligent responses, task automation, and complex workflows.
• React / TypeScript: Built intuitive user interfaces with React and TypeScript, ensuring a smooth and scalable frontend.
• Redux RTK: Managed application state with Redux RTK for optimized state management, enabling dynamic, real-time data updates.
• Vector Databases: Integrated vector databases (pgVector) for embedding support, improving AI model performance in handling complex queries.
• PostgreSQL / Redis: Managed persistent and temporary data with relational and in-memory data stores, ensuring data integrity and speed.
• Kafka: Utilized Apache Kafka for event-driven communication and seamless integration between microservices.
• Spring Security: Ensured the security of backend services with robust authentication and authorization mechanisms.
• CI/CD & DevOps: Integrated continuous integration and deployment pipelines to ensure rapid and secure deployment of features and updates.

• Responsible for the entire software architecture of the parental allowance portal
• iOS and Android app with React Native and Expo, incl. push and OTA updates
• Store releases via App Store Connect and Google Play Console
• TypeScript monorepo for app, website and backend, web with Next.js and Tailwind
• Own promo, voucher and discount engine with contact and segment logic
• Payments via RevenueCat and in-app purchases, authentication with BetterAuth
• REST APIs based on OpenAPI, PostgreSQL with Prisma and Drizzle
• Self-hosting on Hetzner with Docker, Coolify, Terraform and GitHub Actions
• Tests with Vitest, Playwright and visual regression via Chromatic
• Observability via Grafana Cloud and error tracking with Sentry
• Performance marketing via Meta Ads, measured with custom event tracking
• Grew the product to 20,000 app users with a purchase rate of almost 12 %
• Managing Director since 04.2025, responsible for product and technology

• Design and implementation of a system for controlling the complete process of installing, removing, and replacing electricity meters by external service providers for an energy supplier

• Automated retrieval of orders and available devices through defined interfaces (e.g. from SAP)

• Orchestration of the process steps (assignment of meters, processing of meter data, transfer of updated information back to the source system) through a Spring-Boot backend

• Provision of a React-based web client for operational tracking and control of orders, e.g. to continue failed process steps or resend notifications

• Development of a pilot system to control and monitor multiple GoPro cameras
• Implementation of start, stop, status, media, download, and diagnostic functions via COHN endpoints
• Realization of camera detection, single and group control, as well as stable session/keep-alive logic
• Setup of a download pipeline with queue, retry handling, and temporary files
• Consistent session, folder, and file naming for multi-camera recordings
• Integration of provisioning, certificates, and network operations

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

• SAP S/4HANA, OTC, 2nd & 3rd level support, project implementation of S/4HANA Cloud Private Sales & Services
• SAP SCM/OTC/P2P/LE/CS/PS, S/4HANA Private Cloud (Sales, Services), CPI, SAP Business Technology Platform (BTP), EDI, IDoc, ABAP, user exits, SAP Activate, ITIL, SAP Cloud ALM
• Support and consulting for integration of SAP ECC into new business areas in SAP S/4HANA
• Decommissioning legacy systems and implementation of the new harmonized SAP S/4HANA landscape
• Process optimization in SAP S/4HANA and support for daily requests from business users and key users
• Project implementation of S/4HANA Private Cloud Sales & Services
• Responsibility for the SCM stream within the global template
• Process design with Signavio and creation of Business Process Documents (BPD)
• Creation of functional design specifications (FS, TS) including interface design and WRICEF objects
• Ensuring integration of PTP with FI/CO, O2C and EWM through SAP customizing
• Migration from SAP ECC to SAP S/4HANA Private Cloud to replace legacy systems and implement a harmonized system landscape
• SAP BTP & CPI: extension of Cloud Platform Integration (CPI), integration of PTP with FI/CO, O2C and EWM, optimization of cloud-based services
• Analysis and evaluation of existing SCM processes in the SAP S/4HANA Private Cloud environment
• Design of integrated solutions in OTC, P2P, EWM, LE and PP including forecasting and capacity planning
• Extension of transportation processes in SAP TM and SAP LE-TRA to support multimodal transports focusing on rail freight and integration of external rail logistics providers via EDI (VDA, EDIFACT)
• Consulting on further migration to SAP S/4HANA Supply Chain
• Functional consulting on developed supply chain processes
• Management of SAP CCS processes for contract types and bonus agreements
• Execution and maintenance of distributions and settlement keys
• Support for integration of transfer rules into the CCS model
• Documentation of CCS process changes for traceability and compliance
• Customizing and optimization in OTC: condition maintenance for pricing, materials, freight, customers, price & material groups; extension of sales document types, item categories, credit memos, down payments and prepayments with pricing procedure, condition types, access sequences, condition tables, condition records, billing types, invoice types, item categories, sales document types, reconciliation accounts, tax accounts; integration with FI/CO for accounting and financial closing; bonus settlements; delivery process optimization; configuration of delivery schedule types with account determination; creation of schedule line categories for delivery schedules; maintenance of schedule lines for delivery schedule types; schedule line determination settings such as order date, delivery date, availability check rules, returns etc.
• Customizing and optimization in P2P: purchase requisitions, purchase orders, document types (reason codes for ordering, rejection and blocking), scheduling agreements and stock transfer schedules; maintenance of material master and vendor master; payment terms; Incoterms; purchasing groups; purchase prices; quota agreements; contracts; purchasing info records; release procedures (characteristics, classes and release strategies); message control; maintenance of vendor master data; assignment of purchasing info records to materials and vendors; configuration of vendor evaluation with weightings; execution and adjustment of material requirements planning processes; creation of detailed functional specifications for P2P processes such as goods receipt (MIGO), goods issue, purchase requisitions and orders; ensuring data quality and master data maintenance in tables such as MARA, LFA1 and LFB1 etc.
• SAP Fiori: extension and customizing of Fiori apps to improve usability and efficiency; implementation of analytical Fiori apps to monitor KPIs and processes; workflow optimization and UI adaptations for enhanced user experience in SAP S/4HANA Private Cloud
• Process modeling in Signavio; optimization and documentation of business processes; workshops and training on process modeling
• 2nd & 3rd level support in OTC, P2P, CS, PS modules (SCM): incident and change tickets; processing, resolution and documentation of SAP user requests; feasibility analysis for change requests; process optimization; service management with SAP CS; Cloud for Customer (C4C) for modern customer service processes; migration of SAP CS to S/4HANA Field Service Management (FSM); use of embedded analytics for service processes
• Customizing, testing, documentation, training; ensuring integration and collaboration between O2C, P2P and FI/CO modules for supply chain optimization; feasibility analysis; effort estimation; debugging; programming; IDoc and EDI monitoring etc.
• 2nd & 3rd level support in C4C Sales and Services: opportunities, surveys, user creation and authorizations; extension of Business Technology Platform; enhancement of CPI interface; customization of customer and material master data; orders; quotations; equipment; service notifications; surveys; tasks; PS orders; integration of PTP with FI/CO, O2C and EWM; ensuring integration and maintenance of MRP processes etc.
• Responsibility for process analysis and design in export processing, Intrastat and customs management in compliance with international trade regulations (e.g. export control, preference agreements, dual-use)
• Integration and optimization of Intrastat reporting in SAP SD including maintenance of statistical commodity codes, country of origin, tariff codes etc.
• Customizing in SAP SD foreign trade (SD-FT/FTT) for customs-relevant fields and processes
• Coordination and preparation for integration with SAP GTS, including ATLAS reporting, embargo checks, export control and tariff determination
• Collaboration with customs authorities and logistics providers on export declarations and approval processes
• Creation of test cases for customs processes, export documents, commercial invoices, export declarations etc.
• MDG (Master Data Governance): data quality and maintenance of master data in relevant tables (e.g. MARA, LFA1, LFB1); change requests for master data maintenance in O2C/P2P
• SAP S/4HANA migration: support for migration from SAP R/3 to SAP S/4HANA, including data migration, process optimization and system harmonization; support for global rollouts for subsidiaries in multiple countries; experience in developing SAP templates for global implementations
• ABAP: development and optimization of programs to extend functionalities in O2C and P2P modules; debugging and troubleshooting; customization and enhancement of user exits for customer-specific requirements; IDoc and EDI monitoring

• Architecting and developing SaaS platform for graphical definition and execution of pandas data processing pipelines
• Developed POlyglott, an open-source Python CLI tool for translation workflow management featuring PO file parsing, quality linting with glossary enforcement, and DeepL API integration for machine translation
• Developed web application for material compliance management (EU REACH) using Django and modern web technologies
• Built automated infrastructure platform using Proxmox, Terraform, and Ansible — VM provisioning, configuration management, internal DNS, and fleet-wide security hardening across multiple subnets

• In this role, I was responsible as Lead Software Engineer for automating various meat production lines.
• My focus was on developing highly available (High Availability) systems using C/C++.
• I also implemented and supported container orchestration with Kubernetes to ensure smooth and scalable production operations.