Hello, my name is Stefan Sprenger.
I'm a freelance software developer based in Frankfurt.

I build web applications using Ruby on Rails since 2008 and I have 10+ years of experience in developing software for the web.
I've written a book about Rails 3.1 and contributed to several open-source projects including Ruby on Rails, Travis CI and TYPO3.
Feel free to contact me.


Hosted Solr2012 - present

Hosted Solr offers search as a service. Within a few steps you are able to boot your own Apache Solr instance and use it in one of the supported third-party applications.
I was involved in the whole process of building Hosted Solr including initial planning, implementation and rollout.
Hosted Solr is a product by dkd Internet Service GmbH.

Technologies: Apache Solr, Rails 4, Ruby 2, Chef, MySQL, RabbitMQ

Benztown Branding2014 - present

Benztown Branding provides the world’s most powerful imaging libraries with over 226k audio elements, updated and growing daily.
I was involved in the relaunch of Benztown Branding's main application.

Technologies: Apache Solr, Rails, Ruby, MySQL, MongoDB, Redis, Sidekiq


  • Ruby, JavaScript
  • Ruby on Rails, Sinatra
  • MySQL, Apache Solr, RabbitMQ, MongoDB, Cassandra
  • Chef, Vagrant, Capistrano
  • Unix, Vim, Git, zsh, tmux