Gerald Spreer

Freelance Software Developer

I have been developing software for more than thirty years and have worked with a variety of technologies. In addition to many other languages and frameworks, I specialize in Ruby on Rails, Angular and Python while learning Rust and Elixir.
My expertise extends to the modernization of legacy systems, and I enjoy developing innovative solutions for unique requirements. With a deep commitment to Test Driven Development, I not only follow these principles in my everyday work but also teach others about best practices in software development. I usually work for medium-sized companies, municipalities and start-ups.

I am looking forward to discussing your next project with you.

New Open Source


Open Source contributions and code samples

Most of the code that I write is proprietary and a often I cannot even disclose who I am working for. However, here you can see some of the Open Source work that I have done. 


25. Nov. 2023

Red, Green, Refactor — is the way of Test Driven Development. Even though TDD is not a new thing anymore and it has been widely adopted in our industry, in reality, there are many software projects who do not have any test coverage at all and there are many developers who simply refuse to adopt the practice. Extensive test coverages are still very rare.

Read full article

In a typical git workflow, we all use git pull to update our local branches. But I have found that there are some scenarios where that is just not enough.
Especially with workflows that involve development or staging branches. Because staging or development branches tend to be reverted, rebased and reset all the time, any local copy of such a staging branch will be out of date very quickly.

Read full article
Open Source

Life on an infinite canvas

Convay's Game of Life - here on an infinite canvas with some stats. There are controls for stopping and resuming evolution. You can also proceed step-wise.

See the Pen Life on an infinite canvas by geraldspreer (@geraldspreer-pens) on CodePen.

View on


A JavaScript implementation of the classic demo effect...

See the Pen Fire by geraldspreer (@geraldspreer-pens) on CodePen.

View `Fire` on

My Office Setup

Ergodox EZ - Interview

I bought my first ErgoDox EZ a few years ago after I had been struggling with serious back issues.
The split design allows me to keep my hands in a natural position and I have not had any problems since I made the switch.
The Ergodox EZ has changed the way I type and has greatly improved my workfow.

Floss Weekly

In the summer of 2013, I was a guest on Floss Weekly, a well-known podcast about Open Source software.
Many thanks to Randal Schwartz and Dan Lynch for the interview.

It was a great privilege and a lot of fun.
Open Source

The Maker - HTML Editor

the maker This project started as in-house software and was developed in collaboration with Ian Barrow and Brinick Simmons.

The project has been discontinued.

Clients & Projects

neusta enterprise services

neusta consulting, Hamburg

  • Participation in a customer project
  • Development of a recruiting and hiring platform for a leading German company
  • Implementation of several Angular apps for staff and document management
  • Implementation of an applicant portal for high volume recruiting
  • Advising the development team on Test Driven Development, Clean Code and Anguar Best Practices
Technologies: TypeScript, Angular, Jasmine, NgRx, C#, .NET

megorei software gmbh

megorei Software GmbH, Hamburg

  • Participation in a customer project
  • Maintenance and further development of a legacy platform
Technologies: Ruby on Rails, Perl, JavaScript, Docker, Linux, Bash

neusta enterprise services

neusta enterprise services, Bremen

  • Development of several online shops for leading tour operators
  • Development of complex search filters and booking routes
  • Advice on Test Driven Development and Clean Code
Technologies: Ruby on Rails, Angular, NgRx, Elasticsearch, AWS, RSpec, Rothenburg ob der Tauber

  • Development of an event portal for municipalities and event managers
  • This project is a cooperation with Rotabene Media GmbH
Technologies: Ruby on Rails, RSpec, jQuery, Heroku, Amazon S3

neusta sd

neusta software development, Bremen

  • Development of an online portal for booking package tours.
  • Development of a portal and online shop platform based on TYPO3 CMS and SAP Hybris
Technologies: TYPO3, Extbase, Fluid, Solr, AngularJS, SAP Hybris

Der Männerladen

Der Männerladen, Landshut

  • Customer portal for booking events
  • App development for iOS and Android
Technologies: Ruby on Rails, Heroku, Ionic Framework, AngularJS


Rotabene Medienhaus, Rothenburg

  • Development of TYPO3 extensions
  • TYPO3 Support
  • Responsive Web Design
Technologies: TYPO3, Extbase und Fluid, PHP, REST, JSON


bohlen-design, Köln

  • Collaboration on several Ruby on Rails applications
  • System update of a Ruby on Rails project
Technologies: Ruby on Rails, Heroku, Postgres, HTML5, jQuery, Google Maps API

Gewerbeverzeichnis Rothenburg

Gewerbeverzeichnis Stadt Rothenburg

Technologies: TYPO3, Extbase und Fluid, PHP

Trequip GmbH

Trequip GmbH

  • Development of a CRM system in Ruby on Rails
  • Development of plugins, templates and extensions for Shopware.
  • TYPO3 Support
Technologies: Ruby on Rails, OSX Server, PHP, ZendFramework, SOAP

Gewerbeverzeichnis Rothenburg

Veranstaltungskalender Stadt Rothenburg

Calendar extension for TYPO3 as replacement for tx_cal.

Technologies: TYPO3, Extbase and Fluid, PHP

Optik Schmitz

Optik Schmitz, Werdohl

The website of Optik Schmitz in Werdohl was designed and programmed by me and has been maintained to this day.

Technologies: WordPress, jQuery and PHP

Zum Projekt

Open Source