Stefan Kohl - Fullstack Developer (Freelancer)

Graz, Austria

Experience

Feb 2025 - Present

1 year

Fullstack Developer (Freelancer)

Sciuto Software GbR

Implementing a real-time procedural 3D/AR eyelash configurator using Three.js and MediaPipe
Building a full-stack web application with React.js and Python
Consulting on app and web development

Feb 2025 - Mar 2025

2 months

Fullstack Developer (Freelancer)

DieMarktforscher.org

Building a full-stack web application with React.js and Python
Reading and writing Excel sheets in headless mode using Python
Setting up containerized infrastructure on Google Cloud Platform

Oct 2024 - Apr 2025

7 months

Munich, Germany

Fullstack Developer (Freelancer)

Brandeo GmbH

Setting up and customizing an online store in Shopify
Implementing a procedural 3D product configurator for signage products in Three.js
Maintaining infrastructure and providing support to client

Sep 2024 - Dec 2024

4 months

Nordenham, Germany

C++ Developer (Freelancer)

Norddeutsche Seekabelwerke GmbH

Migrating a C++ library from 1997 from 32bit to 64bit and modernizing codebase
Setting up unit testing and introducing modern coding practices into legacy source code
Updating build pipeline and scripts to modern standards

Sep 2023 - Present

2 years 5 months

Mobile App Developer (Freelancer)

Logofin Verlag OHG

Implementing existing therapeutical analogue games as mobile apps in Flutter
Setting up and implementing In-App Purchases for iOS/Android using RevenueCat
Setting up the CI/CD pipeline and handling app store releases
Managing production of animations and VFX outsourced to a designer
Consulting on app development and UX design
Ongoing maintenance and feature development

Feb 2023 - Aug 2023

7 months

Mobile App Developer (Freelancer)

Anyline GmbH

Consulting on cross-platform (iOS/Android) development best practices
Evaluating cross-platform technologies (Flutter and KMM) for SDK development
Providing basic architecture of a new cross-platform SDK
Implementing SDK features for the Android platform

Nov 2022 - Mar 2024

1 year 5 months

Salzburg, Austria

Web/3D Developer (Freelancer)

Forest Mapping Management GmbH

Implementing a proof of concept for rendering a 3D forest based on real-world terrain and tree data (Three.js, WebGL, TypeScript, GLSL)
Evaluating free web-based GIS solutions for integration into the customer's front-end project
Managing outsourcing tasks for front-end developers and UI/UX designer
Managing outsourcing tasks for Flutter mobile app developers

Nov 2022 - Oct 2023

1 year

Cologne, Germany

3D Developer (Freelancer)

Ogulo GmbH

Doing proofs of concept for new features before implementing them into the main project (Three.js, WebGL, TypeScript, GLSL)
Implementing features for the 3D tour viewer (Three.js, WebGL, TypeScript, GLSL)
Participating in code reviews for pull requests (BitBucket, Git)
Consulting on 3D programming techniques

Sep 2022 - Dec 2022

4 months

Frankfurt, Germany

Unity Developer (Freelancer)

Matterkind (Kinesso GmbH)

Implementing a VR experience for presenting the company's profile and portfolio using Unity (C#) and the Oculus Platform
Implementing a VR experience for showcasing the use of the Oculus Platform as 3D DSP using Unity (C#)
Managing 3D environment artists to create content for VR spaces

Aug 2022 - Sep 2023

1 year 2 months

Mannheim, Germany

3D Developer (Freelancer)

Pepperl+Fuchs SE

Implementing a 3D point cloud viewer for mobile devices using the low-level Murl Engine (C++)
Implementing an integration library of the 3D point cloud viewer as a Xamarin component (C#, XAML)
Writing optimized GLSL shader code for decoding stereoscopic image data into 3D points (GLSL ES)
Setting up a CI/CD for bundling NuGet packages with native iOS/Android binaries using GitLab and GitLab Runner

May 2022 - Jun 2022

2 months

Waldshut-Tiengen, Germany

Unity Developer (Freelancer)

CST GmbH

Implementing a proof of concept for measuring tire profiles using smartphone cameras (Unity, Vuforia, AR Core, C#)
Consulting on Unity, Vuforia, and other AR technologies

Apr 2022 - Present

3 years 10 months

Web Game Developer (Freelancer)

PCS AG

Implementing educational games for the web using React Game Engine (TypeScript)
Implementing animations provided by designers using Lottie Player (Bodymovin JSON)
Ongoing maintenance and support

Mar 2022 - Apr 2022

2 months

Web Developer (Freelancer)

Garagible

Developing the app frontend using React.js (TypeScript)
Implementing a 3D garage viewer using Three.js (TypeScript, WebGL)
Implementing tools for converting Blender 3D models into glB/glTF resources
Managing a team of 2D and 3D artists

Jan 2022 - May 2022

5 months

Graz, Austria

Mobile App Developer (Freelancer)

RISE GmbH

Supporting the team of internal and external developers with native iOS development (Swift)

Jun 2021 - Oct 2021

5 months

Horgen, Switzerland

Mobile App Developer (Freelancer)

SUNNYCLOCK AG

Debugging, troubleshooting and refactoring the existing iOS implementation for end-to-end encryption (Objective-C)
Developing new messaging features for the iOS version (Objective-C)
Consulting on iOS development

May 2021 - Mar 2024

2 years 11 months

Frankfurt, Germany

Web Game Developer (Freelancer)

Cocomore AG / Samsung AG

Developing web games for "Samsung Circle", an internal SCORM-based training platform for Samsung employees (JavaScript, HTML5)
Preparing 3D product models for mobile AR applications and providing integration code for the web (JavaScript)
Managing production of 3D models for commercial use

Apr 2020 - May 2024

4 years 2 months

Graz, Austria

Software Engineer (Freelancer)

Green Lobster MT GmbH

Porting the "Welove.Audio" engine to various platforms (Windows, Linux, macOS, iOS, Android) using C++, Java, Objective-C
Developing proprietary binary and JSON data formats and tools for the engine (C++)
Developing audio plugins for Apple AudioUnits and VST3 using JUCE (C++)
Developing engine integration libraries for Unity, Unreal Engine, Android and Flutter (C#, C++, Java, Dart)
Developing a demo game showcasing engine features in Unity (C#, C++)
Developing an audio streaming solution based on Node.js, ffmpeg and Socket.io (JavaScript)
Developing an adaptive audio playback app for tabletop role-playing games in Flutter (Dart)

Aug 2019 - Present

6 years 6 months

Game Developer / Manager

Dyadic Games GmbH

Managing the studio, employees and projects
Serving as creative and technical lead for internal and external game projects
Developing games using Unity (C#) and associated technologies: AAS, URP, ShaderLab, Localization Tools, Cinemachine
Developing procedural modeling solutions for 3D artists (C#, Python, Houdini)

Aug 2019 - Mar 2021

1 year 8 months

Vienna, Austria

Web Frontend Developer (Freelancer)

FPrimeZero GmbH

Developing a 3D warehouse configuration tool using Three.js and dat.gui (JavaScript, HTML5, CSS3)
Developing web frontends (dashboards) in React.js and D3.js (TypeScript)
Coordinating a team of designers and web developers

Sep 2018 - Nov 2018

3 months

Karlsruhe, Germany

Mobile App Developer (Freelancer)

BestFit GmbH

Providing development consulting and support for the team prior to release
Implementing features and UI designs for the iOS app using RxSwift (Swift)

Aug 2018 - Present

7 years 6 months

Mobile App Developer (Freelancer)

Golem Digital

Developing an iOS/Android real estate visualization app using AR with Unity and Vuforia (C#)
Integrating and managing downloadable content for the AR app using Unity's Addressable Asset System
Ongoing maintenance and feature development

Jul 2018 - Jan 2019

7 months

Hagenberg, Austria

Remote

Unity Developer (Freelancer)

REALSIM

Developing MR demos in Unity for Microsoft HoloLens (C#)
Developing a remote control app for a HoloLens MR demo using Unity networking (C#)
Coordinating graphic designers to design assets based on customer requirements

Jul 2017 - Present

8 years 7 months

Web Frontend/Backend Developer (Freelancer)

LIVE:KRIMI Wien

Developing web app frontends based on Backbone.js, Underscore.js, Vue.js, Bootstrap and jQuery (JavaScript, HTML5, CSS3)
Developing REST backends with Laravel (PHP) and MySQL
Developing an ordering, booking and invoicing system using Firebase, Node.js and eTermin (JavaScript)
Ongoing maintenance and feature development

May 2017 - Dec 2018

1 year 8 months

Graz, Austria

Mobile App Developer (Freelancer)

Waymark GmbH

Consulting on app frontend and backend technologies
Developing the iOS version of the app (Swift)
Integrating third-party services like Google Places and Stripe

Mar 2017 - Mar 2018

1 year 1 month

Mobile App Developer (Freelancer)

Quest in Urban Environments (QIUE)

Consulting on mobile app development
Developing the iOS/Android app and implementing UI designs and business logic using Xamarin (C#)
Writing native platform code and integrating it into the Xamarin layer (Objective-C, Java)

Oct 2016 - Aug 2018

1 year 11 months

Graz, Austria

Web Frontend/Backend Developer (Freelancer)

Citycom GmbH

Reviewing and debugging code written by outsourcing contractors
Converting web design mockups to Laravel page templates based on Bootstrap (HTML5, CSS3)
Developing the frontend for a web-based file manager using Angular.js and Laravel (JavaScript, PHP)
Developing internal web platforms for managing and monitoring infrastructure services

Jun 2013 - Oct 2016

3 years 5 months

Graz, Austria

Software Architect / Mobile Games Developer

Cervo Media GmbH

Defining the software architecture of complex mobile game products
Developing core game mechanics, features, user interfaces, visual effects and shaders (C++, XML, OpenGL, GLSL)
Developing tools to optimize the asset pipeline (C++, Bash)
Profiling and optimizing apps for low-end mobile devices
Designing gameplay and levels for a casual game
Leading a team of developers

Oct 2012 - May 2013

8 months

Graz, Austria

Mobile App Developer

Parkside Informationstechnologie GmbH

Setting up the software architecture and data models of iOS apps
Implementing business logic and user interfaces (Objective-C)
Testing and deploying apps to customers and the App Store

Sep 2011 - Sep 2012

1 year 1 month

Graz, Austria

Web/App Developer

Grizzly Werbeagentur GmbH

Developing and maintaining a backend for SMS-based competition (PHP)
Developing native iOS and web apps (Objective-C, JavaScript, PHP, HTML5, CSS)
Developing an online shop based on CakePHP (PHP)

Summary

14 years of professional experience in developing mobile apps, games and web applications. Bringing together elegant technical solutions with appealing visual designs is my driving motivation. I like to see the bigger picture and enjoy tackling new challenges. Throughout my career, I've been part of internationally successful app and game companies (with a customer base of 30+ million) as well as startups and mid-sized companies, taking on lead positions as well as supporting roles.

Skills

Languages: C, C++, C#, Objective-c, Swift, Dart, Kotlin, Javascript, Typescript, Python, Bash, Php, Qml
2d, 3d, Games: Unity, Unreal Engine, Felgo (Qt), Phaser.js, Three.js, Playcanvas, Babylon.js, Opengl, Cuda, Glsl, Hlsl, Shaderlab, Urp, Houdini, Nintendo Sdk, Ps4 Sdk, Xboxone Sdk
Ar, Vr, Mr: Hololens, Vuforia, Arkit, Arcore, Meta Quest
Mobile: Ios, Android, Flutter, Kotlin Multiplatform, Juce, Xamarin, Onesignal, Stripe, Algolia, Braintree, Coredata, Realm, Rxswift, Revenuecat, Cocoapods
Frontends: React.js, Underscore.js, Backbone.js, D3.js, Dat.gui, Bootstrap, Html5, Css3
Backends, Server: Laravel, Node.js, Firebase, Google Cloud Services, Socket.io, Hls, Mysql, Postgresql
Audio: Apple Audiounits, Vst3, Oboe (Android), Ffmpeg
Tools: Git, Perforce (P4), Teamcity, Npm, Yarn, Docker, Jira (Kanban/scrum), Confluence, Visual Studio, Android Studio, Xcode, Eclipse