I have been working with Joomla since 2008. I started with version 1.5 and through v2.5 and v3 I got to the most recent release.
In these years I developed several extensions for the system: from the simplest content plugin to a quite complex IP logging component, a full-equipped astrology component, payment gateways, plugins for VirtueMart e-commerce extension, sport club management component, etc. My specialty is to build interfaces between Joomla websites and web APIs. 
I often have to work with other developers' products, too. I install, configure, debug and even modify them according to my clients' requirements. It could be PHP programming, css, javascript or jquery related issue, I deal with everything.
If you need fast and professional solutions, get in touch with me.