Felix Heller

Mobile Engineer

Frontend Engineer


Hi, I'm Felix, an experienced freelancer specializing in Mobile and Front-end development. I hold an M.Sc. in Business Informatics (1.35 GPA). Having started to create Android apps as a school student, I look back at over 10 years of developing experience. Other than that I enjoy reading (books+coffee=️), concerts, cinema, and cycling. Looking forward to contributing to exciting projects!

I am always open for new challenges, so feel free to drop me a message with project offers.

CV (PDF, German) Contact Me





Here you can find some of the projects I have worked on. As some are subject to an NDA, the final product is not linked, but a work reference is given.



Kotlin Java Android Flutter Dart

AlcoTrack is a blood alcohol content (BAC) calculator, alcohol consumption tracker, and drinking diary, all rolled into one.

  • Over 250.000 downloads
  • Translated by its users into 17 languages
  • 4,6 avg. stars on Google Play
  • 16.000+ lines of code

Smart Caravan App

Flutter Dart Vue.JS NativeScript TypeScript

Development of an app for GPS trackers and caravan sensor monitoring systems.

  • Bugfixing in legacy app (NativeScript+Vue.JS)
  • Development of new Flutter app

Meeting Of Styles Website

Scrum HTML CSS PHP WordPress WooCommerce

Meeting of Styles is an international network of graffiti artists and supporters, which sponsors graffiti mural creation events in over sixteen countries. In 20 years, there have been around 400 events, featuring thousands of artists and attracting thousands of spectators.

  • Re-design and development of the WordPress-based website
  • Setup of the online shop

Tenant App

Angular TypeScript WebComponents NGRX NativeScript GraphQL

New development of a whitelabel app for tenants of housing associations, who can use it to report damage and retrieve documents.

  • Dynamic generation of form UIs depending on the questionnaire from the backend
  • UI programming and connection with GQL API
  • Generalization of the components for whitelabeling

Inventory App

Kotlin Android Jetpack Compose DataStore JCIFS

Development of a simple app for the optimization of warehouse logistics processes.

  • QR code scanning for orders
  • Batch transfer photos to custom folders via corporate WiFi


Pure Kotlin Open Source

DetoxDroid supports its users in the process of "Digital Detoxing" by stripping away annoying features from your smartphone.

  • Fully Open Source
  • Over 150 stars on GitHub
  • 3.000+ lines of code

E-Book & Audiobook App

Scrum Android Java Butterknife/DI EPUB ExoPlayer

Further development of an Android app for borrowing and reading/playing e-books and audiobooks.

  • Co-development on EPUB e-reader component.
  • Connection between app components and server interfaces
  • Refinement of the app's GUI


Java Kotlin

CheatDroid is a developer's toolbox to view, edit and debug shared preferences and sqlite databases of Android apps.

  • Over 2 million downloads on Google Play
  • 9.000+ lines of code



RESQSHIP is an association committed to civilian sea rescue in the Mediterranean. The website serves to educate about the mission and acquire donations.

  • Volunteer work (free of charge)