About me

As you might already guessed from the website title my name is Jonas John and I’m a freelance developer. I grew up near Ulm in Southern Germany but I also lived for a long time in Berlin and other parts of Germany. Currently I am working as a freelance developer in the Düsseldorf area.

Professional Experience

Since I got curious about computers and started with programming about 15 years ago I worked with a lot of different programming languages, systems and frameworks. Here you see a list of my previous professional jobs, but that is just a brief summary of my overall work experience.

Sept 2014 - Present
Freelance Activity (Düsseldorf / Ulm)

Working on smaller customer projects. Also did some proof of concept / research projects with new technologies like: node.js, express.js, node-webkit, mobile app development (with Android), C++ & QT, ...

Oct 2013 - Sept 2014
Consultant Developer at Vodafone Group Services (Düsseldorf)

Worked on internal (web) applications and created data analysis software by using the Perl Dancer Web Framework, JavaScript (Backbone.js & jQuery), MySQL, Shell scripting, Python and much more...

Mar 2010 - Aug 2013
Software Developer at NetSlave GmbH (Berlin)

Helped to develop web based affiliate tracking software. My tasks included Perl development, database administration, front-end development, customer support, UNIX system administration, development environment setup (version control, test system hooks, customer managment, automatized customer deployments) and much more.

Sept 2009 - Feb 2010
Software Developer at novinet GmbH & Co. KG (Ulm / Ingolstadt)

Web application development, web design and Search engine optimization with PHP, MySQL and JavaScript.

Sept 2006 - Aug 2009
Software Developer (Apprenticeship) at artiso solutions GmbH (Blaustein)

Web application development with ASP.net, C# Windows Application development, and production machine development with C# (including threading logic, state machines and working with third-party COM objects).

Sept 2002 - Aug 2006
Software Developer (Trainee / Apprenticeship) at NetSlave GmbH (Berlin)

Web application development, web design, CMS development using Perl, PHP, JavaScript and MySQL.

Key Skills

This is a rather incomplete list of all my IT skills. I’m also quick to pick up new technologies and eager to discover better ways to solve a problem.

  • Front-end web development (HTML5, Bootstrap, LESS, jQuery, react.js, Backbone, …)
  • Perl development (Experience in various frameworks, data processing, best practices, …)
  • C# / .NET Framework (Windows front-end development, State machines, ASP.NET, …)
  • PHP (Experience in various frameworks including Symfony, CI, Wordpress, Drupal, …)
  • Python (Intermediate knowledge, worked on smaller projects)
  • JavaScript backend development (node.js, express.js, socket.io, …)
  • Web service & API development (REST, JSON, SOAP, …)
  • Database management (MySQL, SQLite, MSSQL, …)


  • German (Native)
  • English (Fluent)