Hello! I'm Sebastian, App developer with 5 years experience in smaller and larger Android-projects. Also experienced with creating games for other systems, applications for PCs and Web development. For more details, see Things I can do and Recent work.


Professional experience

What Where When
Android developer CHECK24 Vergleichsportal Profis GmbH 09/2019 - present
Android developer Individual Entrepreneur 04/2017 - present
Software developer Novabit Informationssysteme GmbH 10/2018 - 08/2019
Web developer Freelancer 03/2018 - 08/2018
Student Teaching Assistant University of Ulm 04/2014 - 03/2015



What Where When
Master of Science
in Computer Science
Humboldt University of Berlin 04/2016 - 11/2019
Bachelor of Science
in Media Computer Science
University of Ulm 10/2011 - 03/2016

Things I can do

Recent Work

SwiftTask (2018)

A swift todo app


Add your tasks with all their characteristics like categories, dates and locations in only one line.

The simple input concept not only allows users to add their tasks much faster, but also from Android's notification center without even leaving their current app.


Technical details

  • This is my second app entirely written in Kotlin.
  • The app uses the Room Persistence Library to manage the user's tasks in the SQLite database.
  • Multiple different notification types, such as steady notifications or task reminders. Working together with AlarmManagers and various BroadcastReceivers.
  • Full Android P integration with Shortcuts, notification channels, use of the Direct reply action, Quicksetting tiles, widgets and Google Assistant support.
  • Material design 2 compliant with Bottom App Bar, Floating Snackbar and many more things.

The source code will be available soon.


VIER (2017)

A puzzle game for Android


Fill the 4x4 grid with the same kind of tiles to win the game.

Create combinations of tiles to score whilst trying to reach the goal. Combinations consist of 4 tiles with colors and suits each. The better the combination, the higher your score. But watch out, you have to reach the next stage before you run out of moves!


Technical details

  • The game includes the Google Play Services with scoreboards to compete against friends and the all-time scores. It also enables players to unlock various achievements.
  • The free version runs three different kind of ads, implemented with Google AdMob: A banner ad, an interstitial ad after the game and a video ad to gain coins.
  • If a player gets tired of these, I also included In-App-Purchases with the Google In-App-Billing API (not using any third-party-libraries). By that, a player is able to buy the game and to unlock all themes, if he's to lazy to play for them.
  • For crash-reporting, user evaluation and marketing I also implemented Google's Firebase services.

For more technical details, feel free to look through the App's source code.


VR-Window: Zombies and Panorama (2015)

A demo project for the Android platform. Created in Unity3D with Google Cardboard support.


I created this game and application as a part of my bachelor thesis. It is used to show different concepts of multiplayer interactions between a VR-device and a common smartphone- or tablet-device. It includes a small Zombie-shooter and a panorama-view.

There's a link to some more screenshots below, to which it is referred to in the Features:


Some features

  • The two devices connect via Bluetooth. One is used in a Google Cardboard, which is called VR-device (VRD) from here on. To the second normal Smartphone it is referred to as Second-Screen-device (SSD).
  • Clone: The SSD sees the same as the VRD, but without the stereoskopic view.
  • God mode: The SSD is able to spawn zombies around the VRD (2D I/O vs 3D I/O).
  • Coop: The SSD and VRD fight together against zombies (two different I/Os with the same goal).
  • Panorama: The SSD can show the VRD positions in a 360°-Panorama and/or watch it together.
  • and many more...

The (german) thesis for further infos and features is available below.


A simple calendar (2015)

This is a small selection of UX i made at Timekeeper. It should be noted that these (fully functioning) Activities have been created, when Material design was just approaching and there was no full support by Google at that time.

DayZ database manager (2013)

I hosted a server for the DayZ-game back in 2013. Because there were no tools to manage the database of the game-server, I started to develop my own in Java. In the end I've got a lightweight database-manager with a clean User-Interface.


DayZdbManager is a simple Java-Application, developed with a Swing-GUI. It connects to a standard MySQL-server, which holds player data as JSON-objects.


Zock'n Roll (2010)

A puzzle game for Sony's PlayStation Portable


Sony didn't allow any Third-Party-Applications on their mobile gaming platform. However, some people developed own open operating systems for which the applications where called Homebrews. One created a Lua-Player-Homebrew, which allowed me to build a puzzle game, written in Lua script.


This was my very first bigger project in which I was challenged with the system's limitations: A 222MHz Processor and 32MB RAM. In the end, I got a popular puzzle game with online-highscores and even different supported game-themes. Watch a video of the game below - produced by the dashhacks-website.