Featured Video


The Idea

Since the human brain is incredibly fast in regard to image detection we decide to use this capability for the ticket verification process. Most of the ticket verification process can be done by the app, but the final "does the person have a valid ticket" step has to be done by a person.

Therefore we just need a fast and reliable system to check whether the previous electronic verification has been successfully done or not.

This is where the stickers come into play: Every ticket inspector group gets assigned a random sticker. This can be for example a little animated image of a cute comic dog.

When the user app detects one of the BLE beacons it starts the verification process using the beacon id via the backend and, if successful, displays the sticker on the screen.

Then this sticker can be shown to the ticket inspector as proof of a valid ticket.

Technology Stack


  • Flutter Framework 1.22
  • Dart


  • Java 8
  • Spring Boot
  • Maven

Dev Tools

  • Android Studio 4.1.2 with Flutter Plugin for the App Development
  • Xcode 12 for IOS Tests
  • Netbeans 12 for the Backend Development
  • Gitlab and Docker for Version Control and CI/CD


  • Can't someone just make a screenshot and send it to a friend?

The "screenshot" would have to be a perfectly looped video because the sticker is animated and considering one only has access to the sticker during an inspection this copying would have to be done in the few seconds before one of the inspectors gets suspicious.

Even if someone captures all the used stickers, they only have one try to get the right one if they get inspected. 

  • What if some user is offline or doesn't want to use Bluetooth?

As a fallback a notification is shown which provides quick access to the valid ticket, where a QR code can be scanned to validate it.

The Team

The team consists of Jakob Geringer, Simon Lehner-Dittenberger and Lukas Wallenböck.

All three of us went to the same IT HTL class, then we parted ways:

Lukas and Jakob started studying business informatics and currently doing their master's in AI. Both Lukas (part-time) and Simon (full time) started to work at Cloudflight GmbH (at that time still called Catalysts) as full-stack software developers. Jakob worked at Accenture and decided to focus fully on his studies. 

During the implementation, Jakob and Lukas will lie their focus on app development. Simon will be responsible for the Backend Ticket verification. We all together will work on the video. But nevertheless, we are one team and will support each other as well as possible.