The Web Developer extension adds various web developer tools to the browser.
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
View HTTP headers of a page and while browsing.
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
Add, modify and filter the HTTP request headers sent to web servers. This addon is particularly useful for Mobile web development, HTTP testing and privacy.
FirePHP enables you to log to your Firebug Console using a simple PHP method call.
Not using Firebug 1.9+ on Firefox 8+? See http://firephp.org/
Show the IP address of the current page in the status bar. It also allows querying custom information services by IP (right click) and see location and avaiable vouchers for shopping sites. Additionally you can copy the IP address to the clipboard.
Contextual (inline) unit, timezone, and currency converter on any web site, plus custom conversions for offline text. Shopping assistant also included -- find the best deals online! (Currency conversions and shopping assistant disabled by default.)
Screengrab! saves webpages as images... but not for new versions of Firefox.
FF changes too fast and I don't have the time to maintain it anymore. Bugs have developed that I am not in a position to investigate.
Therefore, Screengrab is EOL.
Collections are groups of related add-ons that anyone can create and share.Explore Collections