React Native
React Web
and Hooks :-)


Please find my services here.

React Native Apps / React Web Apps / React Hooks / Redux State Mgmt

React is fun! And Redux or similar libraries help keeping the state (data) of your site consistent and its complexity manageable. Instead, we can also use React's new feature React Hooks to use simple functions with state to share your data across multiple components.
For superfast first loading we can discuss using SSR (Server Side Rendering) using Next.js for instance.
If you need an installable app instead (iOS & Android), think of React Native, the one-codebase solution which will be coded in JavaScript and JSX - like React Web Apps are.
We can also discuss a PWA (Progressive Web App) approach using service workers along with the browser.

Responsive Design

Being responsive will raise your conversions as you help users find their way. Let's tailor your app for phone, phablet, tablet, and desktop using best fit CSS strategies.

CI / CD / Docker / Kubernetes

"It's not easy being green." - Kermit, the frog. compose-docker up works for development, but where to put it when done? And how? I'm just diving into Kubernetes technology which is very promising.

Web Analytics

Content is king. But new sites and apps are in danger if your legacy sites/pages are still online, but neglected or out of date. Let's also take care of that.

Planning & Scrum

Scrum gets you deliverables every 2-4 weeks. So you can check fastly if you're still on the right path. Also visible progress creates motivation for all. I can assist you as Scrum Master and Developer.

System Analysis

You have a big migration or integration project in front of you? Take your time in analyzing all connected systems and workflows. And come to an agreement about the requirements with all of your stakeholders. I can assist you.

Brainstorming Sessions

Please also invite me for concepting sessions, defining the MVP and target audience, or just to have a coffee or beer and get to know each other (this would be my party of course).


Take advantage of my experience in wholesale, retail, online-banking, telecommunications, online-travel, and, of course, software and app production.

App Portfolio

Apps, ideas, work in progress.

Marry Harry

International Romance

Conny & friends

A cartoon messenger app - on hold

App ideas

What do you think?


Send charming picture messages.


Find new lunch partners.

Noxio Room Sync

Connect to Airbnb & - WIP

Bootstrap & Love

IT Marketing for Siberia


A summary of the last 22 years. Gosh.

  • 2002-2005

    Software Developer

    ASP 3.0, T-SQL, SQL Server, HTML Developer
    (1 year)
    C#/.NET Remoting, PL-SQL Developer using Oracle 9i, UML
    (2 years)
    DMS Software Livelink (OpenText), Developer & Co-Admin
    (1 year)
    CRM Software SalesLogix (Sage), Developer & Admin
    (1 year)

  • 2006-2007

    System Analyst Data Warehouse

    Creating software design specifications for a new financial reporting and billing process after the merger of Sprint and Nextel.
    Proposals and presentations were worked out in cooperation with departments of Finance, Data Warehouse, Infrastructure and Production Support.
    (1 year)

  • 2008-2011

    Technical Lead Freelance Projects

    Implementing a Web Analytics Executive Dashboard for 20+ sites using Piwik, SQL-Server 2008, ASP.NET Frontend (C#, MVC)
    (6 months)
    Migration of client’s Alumni web portal to a new service provider
    (6 months)
    Magento eCommerce Plaform setup and client's product data import
    (3 months)
    Human Resources and Customer Relationship integration projects
    (6 months)

  • 2012-2013

    EBIT, ROI, Cash flow & Break (not even)

    Creating a Sales Exposé for a company in plastics industry.
    The price of the company was determined using a mix of gross rental method and multiplier method while analyzing the EBITs of the latest three years and trying to forecast the following 5 years.
    A share deal was preferred over an asset deal.
    (6 months)
    Taking a break for speeding down and new ideas.
    (1 year)

  • 2016


    Frontend Development

    Due to a confidentiality agreement I cannot give details here.
    (6 months)

  • 2018-2019

    Beiersdorf (BSS GmbH)

    Programming a React/Redux Translator App from scratch, deploying it via Azure DevOps as Azure App Service (Linux Docker Container) using Web Sockets and Azure Active Directory Authentication.
    (3 months)
    Customizing and Integrating a React Web Chat Component via Azure DevOps as Azure App Service into client's Web Portals using Azure Active Directory Authentication and Access Token Management.
    (4 months)

  • 2019

    Volkswagen Financial Services AG

    IT Trainer & Developer

    Due to a confidentiality agreement I cannot give details here.
    (6 months)

  • 2021-2022

    Beiersdorf AG

    Developing a Campus App prototype for iOS, Android & Web including Indoor/Outdoor Navigation, Locker Integration, Canteen Occupancy & Outlook Integration using React Native, Expo, React Native Web & Azure DevOps / Active Directory Authentication.
    (15 months)

  • Since 2014

    Herr Kraatz macht Apps.

    Design and production of Marry Harry - International Romance, available on iOS and Android.

    Design and production of Lunchhopper - Find new lunch partners, available on Android.

    Design and production of SUPERBUDDY - Send charming picture messages, available on Android.

    Development of Conny & friends - A cartoon messenger for children, will be available on iOS and Android. Actually on hold.

    Development of Noxio Room Sync - React Web App to avoid overbookings and sync room rates over multiple channels, will be available in all major browsers (desktop & mobile). Work in progress.

  • Back


Holger Kraatz


In 2000 I first got in touch with IT business - during my internship in a consulting company in Virginia - and immediately became passionate about programming. That's why I started in this industry after finishing my studies in Industrial Engineering and Management. And still glad about this focus on technology.



Herr Kraatz macht Apps.

Holger Kraatz c/o Us+ (Us Berlin)
Kottbusser Damm 103A
10967 Berlin

+49 (0)151 2015 2224
service (bei) herrkraatz (punkt) berlin