Best Firefox Addons for Web Designers/Developers

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Firefox is my favourite web browser, and one of the reasons I like it so much is because there are so many useful and time-saving add-ons for Firefox.  If you’re a web designer or developer who uses Firefox, then you know how helpful a great add-on can be!  To help you save even more of your time, I’ve rounded up my favourite Firefox add-ons for web designers and developers!


Wouldn’t it be nice if there was a fast and simple way to view the differences in HTML code (text) between 2 web pages?  Well, PageDiff, an add-on for Firefox, lets you do just that!  PageDiff uses browser generated DOM compliant view source, and it removes the Doctype declaration and HTML tags, allowing you to ignore the source code and compare just the text content of the web pages.


This Firefox add-on includes a colour eyedropper, the Webpage DOM Color Analyzer, and the ColorZilla Online Palette Viewer, making it a must-have tool for colour lovers!  With the eyedropper, you can get a colour reading from anywhere in your web browser, adjust the colour, and paste it into another program.  The Color Analyzer will create a palette of all of the colours on a given web page, and you can hover over a colour to see which elements use that particular shade, or click on a colour for a list of all of the CSS rules that apply that colour to DOM elements.  With the Online Palette Viewer, you can view a palette, bookmark it, and share it using a social bookmarking service such as Delicious or Google Bookmarks.

XUL Profiler

Need a great Javascript profiler to help you figure out why your code is sluggish?  Then download XUL Profiler, a Firefox Add-on that enables you to track down the pieces of code that are eating up all of your CPU.  XUL Profiler provides you with a graph of the elapsed time in each method, and it creates an animation which dynamically displays the canvas zones being redrawn.

WHOIS Lookup

If you use to find out more information about a URL, then you need to get WHOIS Lookup, an add-on for Firefox.  WHOIS Lookup adds a small Whois lookup button to your browser, allowing you to perform searches for details related to an IP address, domain, or hostname, such as location, network provider, and contact details, with the click of a button!

POW — Plain Old Webserver

If you’re looking for a lightweight and flexible webserver, then you need to download POW — Plain Old Webserver.  This add-on for Firefox allows you to add a server to your web browser by using server-side Javascript (SJS), and POW supports Cookies, AJAX, GET, POST, uploads, Cookies, and SQLite.  POW comes with security features to help you protect your site, and it has been used to create everything from wikis to search engines.

Dummy Lipsum

Dummy text is great for web designers who want to show their clients how text will look in a site’s design before the content is ready, and the Dummy Lipsum add-on for Firefox is a great tool for creating dummy text.  When your cursor is in a text area, a context menu option will appear (“Insert Dummy Lipsum”), and this option will automatically fill the field with dummy text.  Dummy Lipsum will attempt to detect the size of the text area and fill it will the appropriate amount of content, but you can also configure the default values for each type of field.


This is the ultimate Firefox add-on for web development, so you have to download it if you haven’t already.  Firebug provides you with tons of web development tools you can use while you browse websites with Firefox, enabling you to debug, edit, and monitor Javascript, CSS, and HTML live in web pages.  Firebug boasts tons of great features, including the ability to monitor network activity, visualize CSS metrics, tweak CSS, inspect and edit HTML, explore the DOM, and much more!


If you want to improve your website’s performance, then you should download YSlow.  This Firefox add-on uses a set of predefined or user-defined rules for high performance to evaluate your site’s pages, and it will provide suggestions on how you can improve the speed of your website.  YSlow is integrated with the web development tool Firebug, and it includes tools for performance analysis, including™ and JSLint.

Server Switcher

Looking for an easy way to switch between a site on your development server and your live server?  Then download Server Switcher, a Firefox add-on that allows you to easily navigate between websites on your development server and live server with the click of a button!  Server Switcher is a great add-on for web developers who want to be able to instantly see the differences between two websites.


There are lots of add-ons for taking screenshots of web pages, but FireShot is arguably one of the best add-ons available.  Like other screen capture add-ons, Fireshot allow you to  take a screenshot of an entire web page or just the visible portion, but it also includes a set of annotation and editing tools.  With these tools, you can  easily modify your screen captures, as well as insert graphical and text annotations, making Fireshot a great tool for developers and designers to use when working with their clients.

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  1. On June 22, 2010 at 2:12 am

    Travel Blog said:

    Firefox has some great addons for web designers and webmasters as well. This is the main reason why I use Firefox. Thanks for the great articles. I didn’t knew about some the addons.

  2. On December 19, 2009 at 10:05 pm

    aryawan said:

    mozilla firefox is a browser that many in suport of the cool plugins … My favorite plugin is colorzilla, great plugin …

  3. On December 8, 2009 at 2:33 am

    Brad said:

    I just picked up SearchStatus addon today and also NoDoFollow Addon helps you find out if post with links are being backlinked. Right Now its showing the link in your name highlighted in blue which means your url is being backlinked. I’ts pretty neat.

  4. On December 7, 2009 at 3:30 pm

    Lesley Banks said:

    Because a lot of web designers are also involved in the SEO side of things you forgot about a pagerank toolbar addon.

    I use SearchStatus but there are others…useful little tools.

    • On March 16, 2010 at 12:39 pm

      NpXp said:

      Searchstatus is the best addon till date for Firefox SEO enthusiasts. I just love the way it works and gets the information of every website.

  5. On November 27, 2009 at 1:32 am

    Prakas tejo said:

    I agree,,now i use pageDiff add ons on my ff browser,if you belive it’s can make my site load faster.
    Thank 4 the info.