There are lots of firefox addons for web development; here are the best firefox addons for web development I use on a daily basis.
YSlow analyzes web pages and why they’re slow based on Yahoo!’s rules for high performance web sites.
Page Speed is an open-source project started at Google to help developers optimize their web pages by applying web performance best practices. Page Speed started as an open-source Firefox/Firebug add-on and is now deployed in third-party products
Perform multiple validations and take screen shots in one go. This 4-in-1 validator works with external, internal, or local web pages using a local copy of the desktop tool obtained from
Displays a country flag depicting the location of the current website’s server and provides a multitude of tools such as site safety checks, whois, translation, similar sites, validation, URL shortening, and more…
live http headers
View HTTP headers of a page and while browsing.
t will capture what you can see in the window, the entire page, just a selection, a particular frame… basically it saves webpages as images – either to a file, or to the clipboard. It captures Flash too!
adds a menu and a toolbar button to switch the user agent of firefox
the list is a very small selection of the web development addons available, but it contains the addons that I use every day. if there are any others that you can suggest, please comment and ill try them out =)