Portfolio

A printable version of this portfolio is available as a PDF file including the following selection of projects I worked on in the past. {: .print markdown="1" }

Plaid Inc.

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07.2016 – present

Objective-C, Swift, CocoaTouch, Python, Node.js

Plaid Link for iOS consits of the emedabble LinkKit.framework, which provides a quick and secure way to integrate with the Plaid API, handling credential validation, multi-factor authentication, and error handling.

Cocologics GmbH

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07.2015 – 05.2016

Objective-C, Swift, CocoaTouch

ProCamera is an iOS photo, video, and editing app bursting with state-of-the-art technology.

Facts & Figures

In the beginning I was responsible for performance improvements while managing ProCamera's photo library after the implementation switched to the Photos.framework. This involved using incremental change notifications via PHAssetChangeRequests and

Later I contributed user related features such as a customized photo export allowing the user to convert and resize the image and optionaly strip location related metadata from the data.

In order to modernize the application technology I helped moving shared code from static libraries to framework modules.

iwascoding GmbH

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07.2013 – 05.2015

Objective-C, CocoaTouch

Teufel Raumfeld is a multi-room audio system which integrates wireless music streaming into high-quality speakers.

Facts & Figures

My work was to adapt and enhance an existing iPhone application for the iPad. In the beginning that meant creating new and refactoring existing views. As the software matured I moved on to improving the software architecture in addition to regular bug-fixes and maintenance work.

teNeues Digital Media GmbH

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09.2013 – 09.2014

Ansible, Debian, Vagrant, nginx, FastCGI, Python, SixCMS, PHP, Symfony, XMP

Cool Cities is a visual city guide to hip hotels, restaurants, cafés, clubs, shops, and other highlights of exciting cities like Berlin, London, Rome, New York, Paris, and others.

Facts & Figures

As a technical consultant I designed and built the backend server architecture for www.cool-cities.com. The system is orchestrated using Ansible, and on top of it a virtual development environment using Vagrant and Virtualbox is built, matching the production system as closely as possible.

Furthermore I assisted in simplifying and automating maintenance tasks, such as image metadata extraction using pyexiv2, software deployment through Ansible playbooks, and media asset management.

Through code reviews I helped improve the website performance and decrease the load on the server by optimizing database queries.

INSIDE Guidance

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02.2009 – 05.2013

Objective-C, CocoaTouch, Cocoa, CoreData, OpenGL ES, Ruby, CouchDB, Javascript, Vagrant, Chef

INSIDE Mobile is a complete whitelabel framework to create mobile fair guides and manage their content. Based on this platform over 50 applications have been created; to name a few: Art Basel, Baselworld, Bread And Butter Berlin, Gamescom. Notable aspects of the platform are its high configurability and its modular architecture. This gives much flexibility allowing to customize the application structure and design quickly and adapt to the client's and project's requirements.

Facts & Figures

In the bootstrap phase I was the lead architect and developer for the iOS application, server backend, and production toolchain. Designing a custom API to configure and theme views and view controllers as well as data model relations through a single configuration file representing the the overall structure of the application. Building a solution based on SVG where people could visually place exhibitor labels on to floor maps and importing that location data into the application models. Creating data importers in Ruby to allow clients to provide their data via CSV, Excel, XML, or a custom API to synchronize the data into the company database and enriching from additional sources and cross-referencing the data sets.

At first this meant building the iOS application Apart from the application development, backend architecture and programming as well as data modeling a large part was defining and optimizing the workflow through automation for quality, reliability, and ease of use.

txtr GmbH

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04.2010 – 01.2011

Objective-C, CocoaTouch

The txtr application is an eBook reader similar to Apple iBooks. At the time the txtr application allowed to browse a txtr specific store and buy eBooks from within the application.

Facts & Figures

My involvement started with an user interface analysis of a rough iPad prototype based on the existing iPhone application. From that analysis I created a technical concept, which was further refined by txtr. Thereafter I programmed the iPad user interface according to the design and specification of the txtr working closely with their staff.

Discounto GmbH

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01.2010 – 03.2010

Objective-C, CocoaTouch, JSON, HTTP

Discounto presents the latest offers and advertisement brochures from german supermarkets nearby.

Facts & Figures

In the beginning the client and I met a few times to outline a draft for a native iPhone application. Once the client was satisfied with the concept I partnered with a colleague from my network to program the iOS application. It was a rather small project in which I was responsible for all areas of delivering the project: planning, calculating, implementing, testing, etc.

Tech21 Sensor GmbH

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04.2009 – 12.2009

Java, AWT, YAML

Tech21 invents and develops innovative controls for mobile electronic devices. Their sensors are low-cost, robust and touch capable.

Facts & Figures

I was asked to review the software, which displayed the touch input of a sensor prototype on-screen, and present a modular software architecture which allowed for easier configuration and calibration for future variants of the touch sensor. One crucial aspect during the refactoring and enhancement of the code was fine-tuning the algorithm to detect the number and position of touches.

Ledger

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11.2012 – present

C++, Boost, Python, CMake, Texinfo, mdoc

Ledger is an open source double-entry accounting system that is accessed from the UNIX command-line.

Facts & Figures

I use ledger as the base for managing my personal and business finances, it serves me well when calculating project estimates, keeping a timelog for contract work, invoicing, and doing my taxes.

My contributions to the project include several enhancements and bug-fixes, some of those led to fixing the Python module, cleaning up the CMake build process, writing documentation and adding tests to it, and supporting users in IRC or on the mailing lists.