A few people have asked me what FireFox add-ons I use, particularly to aid development work. Here’s a list of the FireFox extensions/Add-On’s I have installed – not all of them are development oriented but I find them all very useful.

• Download Statusbar
  Allows you to view and manage downloads from a tidy statusbar, without that pesky download window getting in the way of your browsing
• Fangs
  This extension creates a textual representation of a web page similar to how the page would be read by a modern screen reader. I find this useful for doing some cursory validation of accessibility.
• Firebug
  Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
• FireFTP
  FireFTP is a free, secure, cross-platform FTP client for Mozilla Firefox which provides easy and intuitive access to FTP servers. Along with transferring your files quickly and efficiently, FireFTP also includes more advanced features such as: directory comparison, syncing directories while navigating, SSL encryption, file hashing, and much more!
• GreaseMonkey
  Allows you to customize the way a webpage displays using small bits of JavaScript. It’s also a cool way of adding functionality to web pages based on come criteria. To get an idea of what you can do with Greasemonkey have a loog at this little demonstration by one of my colleagues Richard Wallis who creates a greasemonkey script that uses our platform API’s to add a Libraries panel to amazon pages.
• IE Tab
  This is an awesome add on. It basically embeds Internet Explorer into Mozilla/Firefox tabs. This is a great tool for web developers, since you can easily see how your webpage displayed in IE with just one click and then switch back to Firefox.
• JSView
  All browsers include a “View Source” option, but none of them offer the ability to view the source code of external files. Most websites store their javascripts and style sheets in external files and then link to them within a web page’s source code. Previously if you wanted to view the source code of an external javascript/css you would have to manually look through the source code to find the url and then type that into your browser. With this nifty little plugin you can download/view all the externally referenced resources.
• Live HTTP Headers
  This allows you to view the Http headers of a page while browsing. Comes in very useful when you want to check or validate the response headers that your application is sending out.
• Quick Locale Switcher
  Allows you to quickly change and apply a different locale from the tools menu. Its very useful if your doing anything with multi lingual support.
• RDF Viewer
  We’re doing a lot of work building applications that use RDF. This tool can be quite useful when inspecting RDF Documents.
• View Formatted Source
  When you use the normal view page source option in firefox, it will render the source exactly how the server outputted it. The problem with this is often contain snippets of code generated by different components and the source is actually very difficult to read through. This little add-on formats the source and provides syntax highlighting and some neat code folding as well as optional CSS support.
• Web Developer
  A Must-have add-on, allows you to perform standards based validation on pages, tinker with browser setting, the list if far too long to mention. If your doing any form of web development this should be a requisite!
• XPather
  Quite a feature rich XPath generator, editor, inspector and extractor. I sometimes struggle with figuring out the xpath to a particular element or node in a file, this makes it very easy! It has a few quirks though.
• Yellow Pipe Lynx Viewer
  RightLynx displays a Lynx view of a web page via right-click or Tool menu. With just one click and without leaving the page (RightLynx opens in a new, small window), preview the page you are on with a Lynx Viewer. You can see what what a page will look like when viewed with Lynx, a text-mode web browser. It is also presumably, how search engines see your site. In addition, it can help determine if web pages are accessible to the vision impaired.