Marcel R. G. Berger

Apps, Platforms & Processes

View on GitHub

Apps and Beyond – Turning Ideas into Products

Hi, I’m Marcel Berger – app developer, software architect, and entrepreneur passionate about building digital products that truly work.


About Me

I build what I imagine – from first sketch to scalable product.
I founded companies, built platforms, led teams, and learned what makes technology valuable – and when it only adds complexity.

Today, I develop apps and systems that combine technical excellence with strategic impact.
As a solopreneur, I handle everything end-to-end: design, UX, backend and app development, cloud infrastructure, automation, deployment, and operations.

I work with Flutter, develop enterprise backends with Java & Quarkus, operate Kubernetes clusters (Civo), manage S3 storages and databases, and automate CI/CD pipelines with GitHub Actions.
The result: robust, scalable, and maintainable systems – built independently and with a high standard for quality and efficiency.


My Products

DokuAI – the app that understands documents.
AI-powered recognition, analysis, and report generation for professionals.
dokuai.app

Sommelio – your pocket sommelier (currently in development).
Personalized wine recommendations based on taste, occasion, and mood.
→ coming soon

PaperlessIQ – your DMS on the go (currently in development).
Smart document management and workflow automation – anytime, anywhere.
→ coming soon

I build products that turn technology into real value.
And if you want, I can build something for you too – efficient, pragmatic, and with the same standards I apply to my own work.


My Focus

Technology for me is not an end in itself – it’s a tool to simplify processes, reduce costs, and enable innovation.
I think in products, not just code. I focus on how technology creates value, not only how it’s implemented.


My Story

I’m not a pretender. I’m Hanseatically direct – born and raised in Osnabrück, with a clear edge, technical depth, and a solution-oriented mindset.
If you’re looking for someone who talks instead of delivers, I’m not your guy.
But if you need someone who implements digital projects pragmatically, takes responsibility, and isn’t afraid of complexity – then welcome.

My story began sometime around 1989 or 1990 – no one really knows anymore.
Facebook didn’t exist, camera film was expensive, and those who wanted to preserve memories needed either a good camera or a damn good memory.
But the ENERGY STAR logo already existed – and I had my first computer: a Weico machine running Weico DOS.

BASIC was my first language – long before I mastered German grammar.
Then came Pascal, C, Java, and Python – and a career that led me through many worlds: from the shell to the cloud, from startups to corporations, from terminals to boardrooms.
I grew up in a world where BIOS was configured by hand, stack overflows couldn’t be googled, and memory management was still a craft.
Those early years still define how I design systems today – efficient, reliable, and built for the long run.

I develop scalable enterprise backends with Java, automate workflows with Camunda BPMN, move complex systems to the cloud, and build native mobile apps with Flutter.
I think long-term, with northern clarity, and develop with one clear goal: software that runs – today, tomorrow, and the day after.

Beyond code, I worked for years in hospitality on cruise ships and in premium hotels. I’ve opened bars, led teams, planned events, and inspired guests from all over the world.
That experience taught me that leadership is more than management, communication is more than meetings, and resilience is more than a buzzword.
I combine the mindset of a host with the precision of an engineer.

I studied business informatics, trained as a restaurant specialist and master bartender (IHK).
I’m a fan of electronic music and long nights – sometimes for coding, sometimes for celebrating. Between lines of code and beats, I find my balance.
Structure, pragmatism, and clarity are always my compass.

I’m like North German weather: clear, direct, and deep.
I analyze like a CTO, act like a captain in a storm – and always stay on course.

If you google me, you’ll find not just code, but concepts. Not just skills, but solutions. Not just projects, but results.
Real. Honest. Efficient.


Professional Background

I developed enterprise software long before “digitalization” became a buzzword.
Whether it’s regulatory financial systems with high security requirements, process platforms in the energy sector, complex identity management solutions, or AI-supported document analysis – I deliver IT that works. Robust, scalable, understandable.

For me, IT is not an end in itself but a strategic tool. I make architecture decisions based on facts – focusing on clean code, maintainability, scalability, security, and operating costs across the lifecycle.

I currently lead Digitalization and Project Coordination in a critical infrastructure (KRITIS) company – responsible for digital strategy, process automation, and secure cloud architectures.
I manage high-impact projects, lead teams technically and organizationally, and build IT solutions that stand up to real-world pressure.

Before that, I was founder and managing director of my own software company for over ten years, where I:

I can plan, architect, develop, operate, and explain software.
Understandably. Responsibly. Reliably.
I combine technical depth with strategic thinking, speak the language of both developers and executives, and always keep the essentials in focus: value, quality, and sustainability.


One Company. Two Minds. Endless Possibilities.

Berger & Rosenstock GbR combines the expertise of Jasmin Rosenstock and Marcel Berger under one brand.
What started as a collaboration became a dynamic partnership at the intersection of technology, business, beauty, and lifestyle – grounded in experience, strategy, and creativity.

Jasmin Rosenstock

Jasmin holds a Bachelor’s in Health Promotion from Coastal Carolina University (USA) and a Master’s in Public Relations and Corporate Communications from the University of Europe for Applied Sciences.
She brings expertise in health promotion, communication, brand strategy, and content creation – bridging academic insight with creative execution.

Marcel Berger

I hold a Bachelor’s degree in Business Informatics from the Technische Hochschule Mittelhessen, combining technical expertise with business acumen.
I’m also a certified restaurant specialist and master bartender (IHK) with additional hospitality management and sensory training, and an IHK-certified trainer (AEVO).

Together, we create digital products, automation solutions, and e-commerce brands, and produce content for YouTube and social media – uniting technology, design, and storytelling for measurable impact.

Whether software architecture, brand development, or content creation – we work hands-on, directly, and with focus on value, clarity, and sustainable success.

berger-rosenstock.de


Technologies & Tools – My Daily Toolkit

Java Spring Boot Quarkus Dart Python Bash C BASIC Turbo Pascal JavaScript TypeScript Go Groovy Swift Flutter Vaadin Angular Vue.js SwiftUI Keycloak OAuth2 SAML JWT Microsoft Entra ID Git GitHub Actions Bitbucket Jenkins Argo CD Docker Podman Kubernetes Portainer Maven Gradle JFrog Artifactory SonarQube SonarCloud Camunda Make.com Zapier Azure AKS Civo Kubernetes Windows macOS Linux Apache Kafka RabbitMQ PostgreSQL Oracle MySQL MongoDB Cassandra Liquibase JUnit Mockito Selenium Thymeleaf Eclipse IntelliJ IDEA DataGrip Android Studio Xcode VS Code Vim Word Excel PowerPoint Miro Jira Confluence SAP


Category Technologies & Platforms
Programming Languages Java (J2EE / Java EE, Spring Boot, Quarkus) • Dart • Python • Bash • C • BASIC • Turbo Pascal • JavaScript • TypeScript • Go • Groovy • Swift
Backend Development Quarkus • Spring Boot • Java EE • RESTful Services • GraphQL APIs • Microservice Architectures
Frontend & UI Frameworks Flutter (iOS & Android) • Vaadin • Angular • Vue.js • SwiftUI • JSP • JSF • PrimeFaces • RichFaces
Identity & Security Keycloak (IAM) • OAuth2 • SAML • JWT • SailPoint IdentityIQ • Microsoft Entra ID
DevOps & CI/CD Git (GitHub, Bitbucket) • GitHub Actions • Jenkins • Argo CD • Docker • Podman • Kubernetes • K9s • Portainer
Build & Repository Management Maven • Gradle • Nexus Repository • Sonatype Nexus • JFrog Artifactory • SonarQube • SonarCloud
Workflow & Process Automation Camunda BPMN • Kogito • External Task Pattern • Make.com • Zapier
Cloud & Infrastructure Microsoft Azure (AKS, Entra ID, Key Vault, Blob & File Storage) • Civo Kubernetes
Operating Systems & Administration Windows • macOS • Linux (Ubuntu, CentOS, RedHat, Debian, Alpine Linux, Raspberry Pi OS)
Event-Driven Architecture & Messaging Apache Kafka • RabbitMQ
Databases & Storage PostgreSQL • Oracle DB • MySQL • H2 Databases • MongoDB • Cassandra • Liquibase
Testing & Quality Assurance jUnit • Mockito • Selenium
Reporting & Template Engines JasperReports • Qute (Quarkus) • Thymeleaf • Freemarker • Velocity
IDEs & Development Environments Eclipse • IntelliJ IDEA • DataGrip • Android Studio • Xcode • VS Code • Vim • Nano
Business Tools & Office Word • Excel • PowerPoint • Miro • Jira & Confluence • SAP
Methods & Practices Scrum • Scrum Master Certified • Scrum Developer • Kanban • Pair Programming • Test Driven Development (TDD)

Contact & Presence

Marcel Berger – IT, Software & Business

Jasmin Rosenstock – Beauty & Lifestyle

Our Company


“The only way to do great work is to love what you do.” – Steve Jobs

Thank you for your visit.
If you’re looking for real substance in the IT world – you’ve just found it.
Honest. Direct. Northerly good.

ImprintPrivacy Policy