Full Stack Developers in Germany

• Developing full-stack applications using React, Python, and PostgreSQL.
• Building AI-enabled solutions leveraging LLMs, agentic workflows, and automation technologies.
• Expanding cloud engineering expertise through hands-on AWS development and preparation for the AWS Certified Developer - Associate certification.
• Contributing to architecture discussions, code reviews, and Agile software delivery practices.

Development and further enhancement of an internal quotation system for managing and analyzing insurance policies. The focus was on consolidating existing systems, establishing modern development standards, and improving testing, security, and deployment processes. Alongside implementing new features, special attention was paid to code quality, security, and performance.

Responsibilities:

• Full-stack development of an internal quotation system based on Spring Boot and Angular
• Design and implementation of a secure Spring Security configuration, including certificate management
• Merging two bounded contexts using Domain-Driven Design (DDD)
• Introducing and integrating Testcontainers for automated integration tests
• Establishing and applying common testing methods (unit, integration, and end-to-end tests)
• Presenting and integrating Cypress as a black-box GUI testing tool
• Improving the CI/CD pipeline through automated versioning and a custom Jenkins Library
• Proof of Concept (PoC) for state management with NgRx in the frontend
• Refactoring legacy code and fixing incorrect Spring Boot configurations
• Training developers in Clean Code, best practices, and the Spring Framework
• Developing a tool to analyze test data and improve quality
• Further development of the existing Cucumber project
• Carrying out dependency updates and analyzing and maintaining the application
• Implementing telemetry and building a Dynatrace dashboard
• Improving technical documentation in line with Arc42 and introducing AsyncAPI

Technologies: Scrum, TDD, CleanCode, Spring Boot, Java, Angular, NgRx, Testcontainers, Cypress, Cucumber, Jenkins, Dynatrace, Docker, Git, Maven, Kafka, Oracle, REST, DDD, Arc42, AsyncAPI, IntelliJ, Jira, Confluence, Windows, Linux

• Designed and developed the central company platform LINK: tasks, CMS, shop, academy, image database, fleet records, and AI assistant in a shared data model on PostgreSQL.
• Supported the transformation of established standalone solutions into a cloud architecture; analyzed the existing data landscape and migrated it step by step.
• Integrated internal and external data sources via APIs and webhooks: Microsoft 365, shop with accounting integration, and manufacturer data.
• Implemented an AI assistant for knowledge access and document analysis, including an approval process before sending.
• Migrated and rebuilt a 49-page website with SEO in mind; launched data-driven tools (Drone Finder, Permit Finder) and lead forms.
• Served as the link between management, operations, and IT: analyzed processes on-site, translated requirements into technical solutions, and trained a team with little digital experience using real work.

Building an open-source CRM with AI integrations

Open-source CRM for small teams, offered as a cloud version and as a self-hosted core product. I own the product technically end-to-end: user interface, business logic, data model, interfaces and operations. Since December 2025, I have been working full-time on Customermates.

Responsibilities:

• Designed and built the CRM workflows for contacts, organizations, deals and tasks, with configurable table and board views.
• Frontend with Next.js, React, Tailwind CSS and MobX; backend business logic with Node.js, Prisma and PostgreSQL, input validation with Zod.
• Built a REST API, webhooks and an MCP interface that lets external applications and AI clients work directly with the CRM.
• Integrated AI assistant based on the Vercel AI SDK, with stored conversations and streamed responses.
• Developed and maintain an n8n community integration for CRM operations and event-driven automations.
• Build, delivery and operations with Docker, GitHub Actions and Vercel, both as a cloud offering and for self-hosting.

Results:

• Product live as a cloud and self-hosted version; source code and integrations public on GitHub.
• More than 200 GitHub stars for the CRM repository (as of 09/2026).

Frontend: TypeScript, React, Next.js, Tailwind CSS, MobX

Backend and data: Node.js, Prisma, PostgreSQL, Zod

APIs and AI: REST, Webhooks, MCP, Vercel AI SDK, n8n

Cloud and CI/CD: Docker, GitHub Actions, Vercel

• Planning and further development of responsive CMS websites
• Frontend development and extension of internal PHP applications
• CONTENS and OpenCms

Worked as an App Engineer as part of the IoT Control team in a React Native Stack.

• Implementing new Components based on the Tonies Design System.
• Improving, extending and maintaining Tonies Design System
• Adding new features like Volume and Playback Control of the Tonies
• Fixed connection issues via bluetooth and wifi
• Removing technical debt and polishing for an upcoming big software and hardware release
• Improving accessibility by optimizing screens and components for usage via screen readers.
• Wrote lots of automated tests to ensure app quality is always stellar.
• Weekly app releases in a high volume workload environment

Results & Impact:

• Improved app stability and connection reliability ahead of a major software and hardware release
• Raised overall app quality through a significantly broader automated test suite, catching regressions before they reached users
• Made the app usable with screen readers, improving accessibility for a wider audience
• Sustained a weekly release rhythm in a high-volume production environment without quality regressions

Technologies: react-native, expo, typescript, react-19, react-compiler, react-navigation, zustand, @tanstack/react-query, i18next, figma, app-store, play-store, sentry, bitrise, config-cat, poeditor

• Applied modern JavaScript features, including ES6+ syntax, destructuring, modules, array methods, and asynchronous programming, to develop efficient and readable frontend code.
• Implemented frontend integration patterns for PHP and Laravel backend services, connecting React interfaces to REST APIs and handling structured JSON data.
• Developed interactive, functional component-based frontend applications using React Hooks, JavaScript, and TypeScript, alongside backend applications and RESTful APIs using Python, Django, Flask, and FastAPI, focusing on reusable components, modular architecture, maintainability, and efficient data processing.
• Maintained a dynamic portfolio platform using PHP, Laravel, Livewire, and MySQL, implementing end-to-end functionality across frontend interfaces, backend services, and database operations.
• Validated server-side request handling, routing, middleware, and form validation using Laravel features to support reliable application workflows and consistent data processing.
• Designed and managed relational database structures using MySQL and Laravel Eloquent ORM, implementing data models, relationships, database migrations, and efficient queries for content management.
• AI-powered applications integrating Large Language Models (LLMs) through external APIs and locally hosted models, exploring practical use cases for conversational AI, intelligent automation, and AI-assisted workflows.
• Built local AI applications and developer tools for running, configuring, and interacting with locally hosted language models, gaining experience with local inference, model integration, and privacy-conscious AI workflows.
• Explored Retrieval-Augmented Generation (RAG) approaches to combine language models with external knowledge sources, enabling context-aware responses based on relevant application data and retrieved information.
• Integrated AI services with backend APIs and application components, developing reusable modules for model communication, response processing, error handling, and data exchange.

• Implementing and extending an Electron app based on TypeScript, React and Node.js to display stream content and technical data
• Extending a Kotlin backend for message processing via Kafka
• Extending various React modules
• Programming custom solutions for customers, including testing
• Creating documentation
• Development in accordance with Scrum processes

Used skills: React, React Hooks, Jest, Vitest, Typescript, Electron, IntelliJ, Vite, Github, Jira, Node.js, yarn, npm, pnpm, Swagger, OpenAPI, Storybook, Docker, Prettier, Eslint, tailwindcss, i18n, GraphQL, CoPilot, Postgres, JSON, Sqlite, trpc, influxdb, Java, Spring, Kotlin, Kafka, Git, Sonarcube

Company in the industrial sector

Projects completed during retraining

• Rebuilt the company website from WordPress using a modern stack with Astro and TypeScript, deployed on Vercel (live at sybarium.vercel.app); replaced the legacy CMS with a faster, maintainable system.
• Reduced page load time by ~80% (from 5 s to under 1 s) through optimization, caching, and asset optimization.
• Developed n8n automation workflows that integrate several REST APIs and internal systems, saving more than 3 hours of manual work per week.

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

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

• Planning and implementation of digital client projects at the intersection of visual design, conceptualization, and technical implementation.

• Development and structuring of well-thought-out websites with a focus on logical user guidance (UI/UX) and functional consistency.

• Advising companies and start-ups on their digital presence and the development of sustainable systems for the long term.

• Continuous integration of modern, AI-assisted development processes (Vibe Coding) to massively accelerate project workflows.

• Development of Java-based applications with a focus on microservices architecture

• Azure, Spring Boot, REST, Kafka, Lombok, Credit

• Lead architect for an enterprise loan digitisation programme, coordinating 12 engineers across five workstreams and serving as final technical authority on system design.
• Cut critical application response times by 68% (display 17.3s → 5.6s; modification 11.8s → 5.0s) through targeted caching, OData query optimisation and lazy-loading refactoring; further optimisation in progress.
• Own production error triage, prioritisation and resolution across a multi-application portfolio supporting live lending operations.
• Design and implement SAP Fiori applications on SAP UI5, TypeScript and RAP, owning delivery from architecture and code through rollout and production support.
• Established C4 architecture documentation and decision records for the full programme, enabling faster onboarding and consistent cross-workstream design governance.
• Co-managed S/4HANA release cycle alongside primary responsibilities, coordinating directly with SAP support to resolve critical system issues across the portfolio.