Mozilla Firefox is a very popular browser, especially among web designers and developers. These days, with such a crowded field, staying at the top of the browser heap takes a lot of work. One of the factors that make Firefox so well-liked is the huge library of great extensions that enhance your browsing experience. Among the massive list of add-ons, many are vital to web designers and developers. If used, it will make your workflow quicker and more productive.

1.Web Developer

Web Developer`s tool bar probably will become one of the best plugins You`ve ever seen. It comes with his own tool bar that gives many useful tools for analyzing, validating and optimizing web-pages. The great thing about this plugin is that it’s on a few different browsers, so if you switch between them you will be able to use the same plugin on all.


Firebug is pretty similar as web developer, but it comes across with few different powerful options. You have an ability to edit, debug, and monitor CSS, HTML, and JavaScript right in any web page.


ColorZilla offers You an advanced eyedropper, colorPicker, page Zoomer and other colorful goodies.


Little Firefox extension that enables you to draw a ruler across any webpage to check the width or height of a element.

5.HTML Validator

This plugin displays the number of found errors of the site you are viewing. It adds HTML validation inside Firefox and Mozilla.

6.IE Tab

Pretty handy extension to see how your site is displayed at Internet Explorer.


YSlow, a Yahoo product, analyzes web pages and tells you why they’re slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool.
This plugin completes FireBug functionality to make Firefox an unbeatable web development tool.


Allows you to customize the way a web page displays using small bits of JavaScript;


FireFTP is simply an FTP client built into the Firefox browser. Important thing it is free and you can flip to it just like any tab in your browser.

10.Live HTTP Headers

It allows you to view and analyze HTTP headers (requests and responses) in web-browser with several useful features built-in. It’s great tool for watching a series of HTTP requests and their result codes.


Screengrab saves entire web pages as images. This tool will allow You to take screenshots of what is currently on your screen – you can even choose the portion of the screen you want to “grab”!


StumbleUpon helps you to find new sites very easy.If you are a web-developer, StumbleUpon can drive a huge amount of visitors to your website.

13.SEO for Firefox

Excellent plugin for all those, who like to watch statistics right into Google and Yahoo search results. You can get Alexa, Google PageRank, Tehnorati rankings and many other useful data. Plugin You can`t live without!

14.Adblock Plus

Adblock is an adblocker and really helps to get rid of unnecessary ads and banners, to browse web pages much faster.

15.Delicious Bookmarks

Delicious bookmarks is official Firefox addon for It integrates your browser bookmarks and tags, to keep them in order and “easy to find” way.


Not supported at Firefox 3.0

You can check out all the HTML tags right on the page without using the view page source option. Unfortunately not yet supported at Firefox 3.0


With this extension you can view CSS properties of related page elements. Very handy, when You got large CSS file with styles overlapping each other, to analyze why something is not displayed in the way You wanted.

18.Foxmarks Bookmark Synchronizer

If you use Firefox on more than one computer, you’ll want Foxmarks. Install Foxmarks on each computer, and it will work silently in the background to keep your bookmarks synchronized. Similar as


This tool can be used to clean page from unwanted banners and ads, especially prior to printing a page. Pretty useful for web developers for analyzing the structure of a page.

20.Tab Mix Plus

If You always have many Firefox tabs opened at the same time, then you need to have this plugin. This plugin provides better management of these tabs.


Winner of the “2006 PC World World Class Award”, good choice for blocking JavaScript, Java and other executable content in certain pages You don’t trust.

22.Unhide Passwords

Unhide Passwords is a tool for everyone who is bad at remembering or typing passwords correctly. It’s good for using at home, but shouldn’t be used at public accessible PC!

23.Image Zoom

If you have ever had an image that was too large to fit on your screen or too small to see the finer detail in your browser or email, then image zoom can help. Image zoom gives you complete control of the size of most images displayed in mozilla based software. Both individual images or whole pages of images can be zoomed.

24.JavaScript Debugger

A powerful JavaScript debugging environment for Mozilla based browsers.


FireShot is a Firefox extension that creates screenshots of web pages. Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify captures and insert text and graphical annotations.

26.IE View

Lets you load pages in IE with a single right-click, or mark certain sites to *always* load in IE.

27.Dummy Lipsum

This interesting add-on generates automatically “Lorem Ipsum” dummy text. I found it to be pretty useful as web designer.

28.Font Finder

Just highlight and right click to see all of the styling information you could require including font-size, font-family, color (in both hex and RGB), line-height, letter-spacing, and much much more..

29.Opera View

Extension based on IE View. If you want quick view in opera, just right click somewhere on page and choose “View This Page In Opera”.

30.Total Validator

Provides true HTML validation (HTML 2.0 to XHTML 1.1) using the official DTDs, plus added attribute checking. So you no longer have to put up with the limitations of the W3C validator (no type checking) and tools like HTML Tidy which interpret the standards incorrectly (they don’t use the official DTDs).

Also performs accessibility validation (WCAG, US-508), broken link checking, spell checking (5 languages), and takes screenshots using 32 browsers on Windows, Linux, and OS/X.


A developer tool for interacting with web services and other web resources that lets you make HTTP requests, set the entity body, and content type.


Truly a time saver if You’re experimenting with the CSS style of your site. Avoids the modify,save,upload,refresh,repeat cycle.


Full-Screen, 3D – PicLens transforms your browser into a visually stunning experience for finding and viewing online photos and videos.
Work on : YouTube, Google Images, Flickr, FaceBook, Myspace, Photobucket and more..

34.RSS Validator

Validates a page using the W3C RSS Validator.

35.CSS Validator

Validates a page using the W3C CSS Validator. Adds an option to the right-click context menu and to the Tools menu to allow for easy validation of the CSS of the current page. Opens the results in a new tab.


Not supported in Firefox 3.0

A powerful extension to minimize Windows versions of Firefox, Thunderbird, Mozilla Suite, and Nvu to the system tray.

37.Tab Scope

Shows a popup on tabs and enables you to preview and navigate tab contents through popup. Very useful to help navigate between many tabs.


Not supported in Firefox 3.0

Fasterfox allows you to tweak many network and rendering settings such as simultaneous connections, pipelining, cache, DNS cache, and initial paint delay.

39.Server Switcher

Server Switcher is a navigational help tool for web developers. It allows you to easily switch between sites on your development (hosting the temporary version you are currently working on) and live servers, so that you can immediately see the differences.

40.Smart Bookmarks Bar

Smart Bookmarks Bar modifies the bookmarks bar to show bookmarks icons only.
Bookmark names will be displayed on mouse over. This feature can be disactivated if you just want icons without the rollover effect.

41.Favicon Picker

Not supported in Firefox 3.0

Tired of that boring default icon next to your bookmarks? This extension adds a interface allowing you to pick the icon for each of your bookmarks.

42.Download Statusbar

View and manage downloads from a tidy statusbar – without the download window getting in the way of your web browsing.


Stylish is a Firefox, Thunderbird, Flock, SeaMonkey, Mozilla Suite, and Songbird extension that allows easy management of user styles. Stylish is to CSS what Greasemonkey is to JavaScript.

44.Selenium IDE

Selenium IDE is an integrated development environment for Selenium tests. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests.


ScrapBook is a Firefox extension, which helps you to save Web pages and easily manage collections. Key features are lightness, speed, accuracy and multi-language support. My personal one of favorites.


Platypus is a Firefox extension which lets you modify a website from your browser. In addition to that you can save your modifications as a Greasemonkey script to make them “permanent”!


Very beautiful addon – automatically changes firefox tab color and makes easy to distinguish one from another.

48.Window Resizer

The Browser Window Resizer is useful for testing different screen sizes.
Supports the 640×480, 800×600, 1024×768, 1280×800, 1280×1024, 1600×1200 resolutions.

49.Autofill Forms

Autofill Forms enables you to fill out web forms with one click or a keyboard shortcut.


Saves and manages frequently-entered text for later pasting into Web page forms in Firefox or email and newsgroup messages in Thunderbird. Pasting a clipping is accomplished with just two mouse clicks, eliminating the hassle of retyping or repetitive copying and pasting.

So that`s all folks! I hope You will find those links useful, personally I did!

What Firefox Addons do you use?
Why do you use them? Join us in the comments!