Today Firefox is a very popular browser especially among web designers and there are a lot reasons for this kind of popularity. Firefox provides an endless amount of functionality that you simply won’t find in any other modern Internet browser. Firefox has some cool add-ons which make the job of website designers much easier. There are many useful add-ons for Firefox out there and we use several pretty much every day for work. In this article I’ve listed 30+ Useful Firefox Add-ons that every designer should know about.