Greg Molnar


I am a UK based independent consultant. I focus on Ruby and Ruby on Rails development and on penetration testing.
I usually help businesses and organisations to reduce costs by automating repetitive processes and to turn ideas into a working and secure product.

Some of my recent projects includes Prowll (The UK's fastest growing marketplace), Room for Tea, Catapult (I've built the backend for the app with Rails), (a ruby tutorial site).

I try to contribute to open source projects as much as I can. I am a Rails contributor, you can view all my contributions on my Github profile but here is a gist if them:

I am also the author of a book about RubyMotion: Hybrid Development with RubyMotion



28 Oct 2015 . tech . Prevent information leaking in Rails Comments

By default Rails sets the Cache-Control HTTP Header to max-age=0, private, must-revalidate, which means the browser needs to revalidate the page on each request, BUT the browser still stores the cached version of the page. The problem with this, if a user clicks the back button of the browser, it won't revalidate the page, it will just simply load the page from it's cache. This can lead to serious information leaking, if you a user logs out from an application and someone else sits to that computer and navigates back in history. A more advanced...

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  • February 2015 – Today

    Freelance Developer

  • May 2014 - February 2015

    Senior Ruby Developer at MWR Infosecurity

  • September 2012 – May 2014

    Freelance Ruby Developer

  • September 2010 - February 2012

    Senior Developer at Clockwork Marketing and Direct Mail Ltd

  • September 2009 - September 2010

    Freelance PHP Developer

  • October 2008 - September 2009

    Web Developer at Clockwork Marketing and Direct Mail Ltd


Send me an email if you would like me to code for you or if you want me to penetration test your application or network!