Flutter - Developer Expert & Trainer

9/2020 – 11/2020

Implementing the base app structure for the Vjumi Flutter app to be further developed
by internal developers.
Hand-over to internal developers and training in topics like Clean Architecture, Clean
Code, DI, testing, TDD and widget management in a custom widget library.

Software Architecture, Mobile Application Development, Softwareentwicklung (allg.), Dart, Flutter, Representational State Transfer (REST), Schulung / Training (IT), Testen

7/2019 – 3/2022

Implementing new Flutter App for Android and iOS for both MediaMarkt and Saturn with
complex project requirements:
• Project set-up based on Clean Architecture
• MediaMarkt and Saturn Apps from one code base
• Different flavors for the 11+ supported countries
• Modular and scalable codebase to support growing team, scaled from 3 to 10 devs
• Domain layer 100% unit tested
• Data layer 100% unit and integration tested
• UI layer partly widget tested
• UI Component Library for separating UI complexity regarding MediaMarkt and Saturn
branding requirements
• Automated build pipeline on CirleCI with checks for code compliance, test stability
and release management to multiple test environments and App Stores (Google and
Apple) with automated change log generation
• Mentoring multiple Android and iOS developers of different skill level from Junior to
Senior in Dart and Flutter
• Responsible for hiring and mentoring new employees

Software Architecture, Mobile Application Development, Softwareentwicklung (allg.), Dart, Flutter, Graphql, Recruiting, Representational State Transfer (REST), Schulung / Training (IT), Testen

10/2018 – 5/2019

Developing a B2B Canteen digitalization App in Flutter with Clean Architecture for
Android and iOS for the Start-Up MealPro. The App is a White-Label solution and
therefore capable of being built individually for multiple clients from one codebase by
specific Gradle rules (Android) and highly customized Xcode Build rules (iOS). The build
process is automated and streamlined with Fastlane and releases versions to Fabric Beta
for testing by default.
Implemented an Admin Portal web frontend in Vue.js to easily manage the data on
Firebase for each client individually.

Software Architecture, Mobile Application Development, Softwareentwicklung (allg.), Dart, Flutter, Representational State Transfer (REST), Testen

8/2018 – 6/2020

• Training the Android and iOS teams in Clean Architecture
• Introducing Clean Architecture to the existing Android App
• Extracting modules from the existing code to fit best with both the clients
requirements and the architecture pattern
• Replacing existing web views with native counterparts
• Bug fixing and improvements
• Integrating an NFC Scan feature into the existing Android and iOS Apps
• Introducing Flutter to the company by implementing a POC and presenting the
benefits and drawbacks of the technology
• Part of the core maintainer team for a back-end orchestration service (aka. BOS or
BFF) running GraphQL in Node.js with TypeScript
• Introducing concepts of Clean Architecture into the BOS Layer for more efficient
collaboration

Software Architecture, Mobile Application Development, Softwareentwicklung (allg.), Android, Android Entwicklung, Dart, Flutter, Graphql, Kotlin, Representational State Transfer (REST), Schulung / Training (IT), Testen

11/2017 – 7/2018

Improving the existing Rewe Android App as part of a team with about five members (fluctuating). Teaching the team on how to implement Clean Architecture properly.
Development of the first feature in Clean Architecture as a template. Helping the team to implement new features in compliance with the Clean Architecture layers. Trying to transition the team to follow the TDD practice.

Mobile Application Development, Android, Android Entwicklung, Java (allg.), Kotlin, Schulung / Training (IT), Software Architecture, Softwareentwicklung (allg.), Testen

5/2017 – 4/2018

Technical Leadership in developing the cross-platform App using Flutter with Clean Architecture and the back-end using TypeScript. Technical concept, software design and hardware architecture, planning and execution.

Mobile Application Development, Dart, Flutter, Representational State Transfer (REST), Software Architecture, Softwareentwicklung (allg.), Testen

12/2016 – 7/2017

Technical concept and development of an access solution for Vodafone employees. The project focused on developing an app that helps employees transition from their existing plastic access cards to a Sim-Card based Solution.

Kotlin, Amazon Web Services (AWS), Android, Android Entwicklung, Java (allg.), JavaScript, Mobile Application Development, Software Architecture, Softwareentwicklung (allg.), Testen

6/2016 – 11/2016

Creating a Passbook SDK for Vodafone Wallet App.
Technical concept and development of a library for the existing Vodafone Wallet Android App.

Mobile Application Development, Android, Android Entwicklung, Java (allg.), Software Architecture, Softwareentwicklung (allg.), Testen

10/2015 – 9/2017

Improvement and feature development for the existing WDR Android App. Optimization of existing code, as well as bug fixing and maintenance of existing features.

Mobile Application Development, Android, Android Entwicklung, Radio, Java (allg.), RTCP (RealTime Control Protocol), RTSP (RealTime Streaming Protocol), Software Architecture, Softwareentwicklung (allg.), Testen

5/2015 – 6/2015

SparkassenScan!
Creating an App focused on the metaio augmented reality SDK for the Sparkasse Mönchengladbach.

Mobile Application Development, Android, Android Entwicklung, Java (allg.), Software Architecture, Softwareentwicklung (allg.), Testdesign (IT), Virtual Reality

4/2015 – 8/2015

CarUnity Car sharing platform.
Development of the CarUnity Android App as part of a small team.
No further details because of an existing NDR.

Mobile Application Development, Android, Android Entwicklung, Java (allg.), Software Architecture, Softwareentwicklung (allg.), Testen

4/2015 – 6/2015

Tattoo Erotica
Technical concept and development of the augmented reality Android App for
Germany’s biggest erotic tattoo magazine.

Software Architecture, Java (allg.), Mobile Application Development, Softwareentwicklung (allg.), Android, Android Entwicklung, Testen

12/2014 – 5/2015

Technical concept design and development of an app for the modernization of electronic control systems. Preparing an Android tablet as state-of-the-art replacement for a membrane keyboard. Connecting the Android App to the proprietary System by developing a low-level communication system based on the Modbus Protocol.

Software Architecture, Mobile Application Development, Softwareentwicklung (allg.), Android, Android Entwicklung, Representational State Transfer (REST), Testen

8/2014 – 11/2014

Game design, technical concept and development of a multiplayer game based on the Unity3D game engine. Development of a back-end system for hosting the game logic.
Implementation of a client-server communication protocol. Modelling of 3D game elements.

Testdesign (IT), C#, Java (allg.), Android, Android Entwicklung, Mobile Application Development, Software Architecture, Softwareentwicklung (allg.)

2/2014 – 5/2014

marktcom – Die Flohmarkt App
Technical concept and development of the marktcom.de Android App.

Java (allg.), Android, Android Entwicklung, Mobile Application Development, Representational State Transfer (REST), Software Architecture, Softwareentwicklung (allg.), Testdesign (IT)

10/2013 – 11/2013

Finishing an Augmented Reality Android App based on the meatio-SDK. Compiling, and publishing on Google Play

Android, Testen, Software Architecture, Android Entwicklung, Java (allg.), Softwareentwicklung (allg.)

11/2012 – 11/2013

Development of the ADAC Android App for searching camping sites in Europe on the ADAC database, with user data synchronization using Google Drive.

Android, Android Entwicklung, Java (allg.), Mobile Application Development, Software Architecture, Softwareentwicklung (allg.), Testen