Freelance Consultant

As a freelance consultant I solve the challenges of my clients in various areas:

Web & Mobile Applications, Infrastructure/DevOps
Training, Analysis, Restructuring
Strategy, Technology, People, Processes

Whether challenging "greenfield" projects, refactoring legacy systems or "rescue missions" - I solve problems. Using the right tools, direct communication and agile methods.

  • Team Server Migration/Upgrade/Development 2013
    SAP Center of Excellence, Walldorf (via Gulp)

    Migration of an existing large Redmine instance, upgrading to the latest version, new development of Redmine plugins.

    Redmine, Ruby, Chef
  • Stealth Mode Startup 2013
    Rails 4 (beta), RSpec, Turnip/Gherkin, Devise, PostgreSQL, Chef
  • Datacenter Management (1&1, Karlsruhe) 2012

    Analysis, consulting, maintenance, extension for a datacenter management application of a very large and well known European ISP.

    Ruby, JRuby, Rails 2, Rails 3, PostgreSQL
  • Event Organization Platform (Hotel & eventbs) 2011, 2012

    Built an application to allow event planners to navigate through and search for different types of event service providers (e.g. location, restauration, …) based on comprehensive search settings.

    Ruby, Rails 3, Postgres, Solr
  • Video Platform 2011

    Prototype development of a vertically scalable video platform. Consulting, training and development.

    Rails, MongoDB, Redis, Chef, Vagrant
  • Mobile Gaming Backend Provider ( 2011

    Extension and refactoring, in-app purchase, leaderboards, achievements. DevOps consulting

    Rails, RSpec, Chef, Postgres
  • Audio/VOIP-Application (Pointoo/ GmbH) 2010

    Developed a VOIP application that allows user to submit audio commentary by telephone (PSTN via SIP) for POI / directory site.

    Ruby, Asterisk, Padrino, Redis
  • User Generated Content Site (Pointoo/ GmbH) 2010

    Automated server setup with Chef. Ubuntu virtualization with KVM.

    DevOps, Chef, Cloud-Computing, Virtualization, Routing
  • DIY-Community (BurdaStyle) 2009

    Internationalization, localization, integration with external systems. Customer from publishing industry.

  • BusinessLive 2008

    Social network focused of connecting employers and employees using profile matching (Holtzbrinck eLab).

  • AllSecur 2006, 2007 (then: "Allianz24")

    Extension of the existing direct sales plattform of a leading insurance company.

  • Yahoo!/FIFA 2006

    Part of the Yahoo team that built and managed the official FIFA World Cup 2006 websites in various languages.

  • Tiscali Games GmbH 2003, 2005

    Created a recurring billing system for online games.

  • Car Rental 2003—2004

    Extension and maintenance of a car rental web application.

  • GmbH 2000—2003

    Launched Amazon Marketplace in Europe. Localization, customizing for the German version.

A list of the most important technologies I worked with:

Programming Languages

  • Ruby
    MRI: 2.x, 1.9.x
    JRuby: 1.7.x
  • JavaScript
  • Objective-C
  • Perl 5, PHP, Python (In migration projects to Ruby, only)

Agile Methods & Tools


Databases & Search

  • PostgreSQL
  • Redis
  • Neo4j
  • elasticsearch
  • Solr
  • SQLite
  • Memcached
  • MySQL
  • MongoDB

DevOps & Operations

CloudOcean Mobile Application, 2013-2014

( was discontinued in 2014)

CloudOcean was a native iOS application for iPhone, iPad and iPod touch (3rd generation) to manage virtual servers with the popular cloud hosting provider

Using CloudOcean you can quickly launch a new server instance or scale an existing instance to changing requirements.

Existing SSH applications are integrated when they implement the ssh:// url handler.

In addition to the Rubygem and a plugin for the DevOps framework Chef, this is my third project around

Is it Rails? Web Application, 2009-

This application provides a quick and easy way to find out whether a web application is based on Ruby on Rails or not.

It uses a specially developed fingerprinting engine that makes an assessment in terms of specific characteristics of Rails apps.

Started in early 2009 over 7,000 applications have been identified as Rails applications.

  • Ruby
  • Ruby on Rails
  • RSpec
  • Unicorn
  • Twitter Bootstrap

digital_ocean RubyGem, 2013

DigitalOcean is an US cloud hosting company with data centers in New York and Amsterdam. My rubygem provides an easy to use interface to their REST-API to manage virtual servers. Uses travis-ci, codeclimate and coveralls to ensure code quality and test coverage.

details on

knife-digital_ocean RubyGem, 2013

To integrate DigitalOcean into the Chef DevOps framework, I've created a plugin to chef's cli knife. This allows bootstrap servers with a single command line command. Supports traditional chef-server environments and chef-solo using knife-solo or custom bootstrapping commands. This is one of the very few open source plugins to knife that has some tests at all.

details on

hetzner-api RubyGem, 2010

I have published and maintained an open source Rubygem to interact with their API. This allowed me to automate some infrastructure tasks using Ruby. With the rise of more scalable cloud providers like AWS, DigitalOcean or Heroku, this is probably only be interesting for legacy projects.

details on

onlinebrief24 RubyGem, 2013 is a German pdf to snail mail service. My rubygem provides a fast and easy way to deliver those pdfs to their API using SFTP.

This allowed me to automate various invoicing workflows within a SaaS application.

  • Ruby
  • RSpec
  • net-sftp

Also: Travis-CI for continuous integration and Code Climate for code inspection.

details on

mvg-live Rubygem, 2012

Because there is no official way (no OpenData) to check the live timetable MVG live of the city-owned public transportation of Munich (MVG) on the command line, I've reverse engineered their GWT-based AJAX data feed and build a small ruby application for the console. An extra option to output JSON instead of human readable text is included.

details on

Sponsoring & Support

I've supported the following projects and events financially:

Ruby User Group Munich 2008-2011

Founded the user group, did all the organization work and held some talks.

edX / BerkeleyX

  • CS169.1x: Software as a Service

    Berkeleyx certificate 169.1x

    CS169.1x teaches the fundamentals for engineering long-lasting software using highly-productive Agile techniques to develop Software as a Service (SaaS) using Ruby on Rails.

  • CS169.2x: Advanced Software as a Service

    Berkeleyx certificate 169.2x

    CS 169.2x is the second half of University of California, Berkeley's semester long course on Software as a Service.

Contractual Basis

I am available for projects both directly as a freelancer or as part of Moriz GmbH.

I usually bill by the hour. Due to lack of sustainability for both sides and uncontrollable project risks for me I'll reject fixed-price projects, unless a sufficient specification is provided.

I am happy to create a specification as part of a consultant project with hourly billing.


My fees vary according to the task, location and challenges to be solved.

What I prefer:
  • Agile environment with good test coverage
  • Direct collaboration with decision makers and product owners
  • Project duration longer than 6 months
  • Remote work or
  • On-site project in Berlin, Munich or Vienna.
Things that I surcharge for:
  • Legacy projects (depending on the technology, code quality and scope)
  • No agile project management
  • "Red Tape"
  • Short-term "emergency" mission

If you need a third-party recruiter to hire me, this will cost you additional money (~15-30% depending on the recruiter). I can't control this commission.