Best Firefox add-ons for developers and designers

Firefox browser add-ons

Add-ons can be useful as well as time-saving for developers and designers alike. Take a look at some of the great add-ons you can attach to your Mozilla Firefox browser to make your life easier.


Adds a ruler across any web page of your choice in order to check the width, height and alignment of page elements. This will help you to see if elements are what you intended them to be when creating the CSS.


This tool allows you to choose a colour that you have found on a page, get the code for it and then paste it into your coding program. It also comes with page zooming functionality where you can also measure the space between two points on a page. It has a built-in colour palette browser and saves your most-frequently used colours for later use.


This add-on allows you to highlight a font that you like on any page, then right-click on your selection and choose “FontFinder” in the menu. Here you will be able to see what family the font belongs to and any other CSS stylings that come along with it (letter spacing, etc.) You can then paste it into your own web page.

Dummy Lipsum

This is great for generating text when designing and developing a website in order to check dimensions and so forth. It generates the standard Lorem Ipsum latin text that you will find most everywhere as a replacement for the real text. It requires a minimum text length of 5 words.

Web Developer

This add-on has all the features you will need to debug a page. It creates a toolbar at the top (where your bookmarks bar usually is) and from there you can access a plethora of features. It has a disable tool for turning off Java, Javascript, background colours and so forth. You can toggle image displays, control the use of cookies, resize windows (good for responsive design testing), display line guides and add a ruler. You can also “view source” by launching it in an editor of your choice. These are only some of the features you will get with this add-on and it is undoubtedly one of the best out there.

SEO Toolbar by Moz

Some people may be familiar with the Moz blog (previously known as SEOMoz). They specialise in everything SEO-related and have become known as trendsetters in the industry. Now they have created a toolbar specifically for people into SEO. This toolbar will allow you to access Domain Authority and Page Authority for the pages you visit, conduct keyword research through Google as well as Bing and create custom searches by search engine, country and city. You can export any important data from this add-on to an Excel document and analyse links on the Internet. You can analyse metadata, measure page loading speed and check redirect paths.

Image Zoom

This great little add-on allows you to zoom in on any image on any web page. They have pre-selected zoom settings or you can set ratios by hand. You can also rotate images left, right or 180 degrees. Zoom controls are linked to the mouse buttons (for example, holding in the left mouse button and spinning the wheel will either zoom in or zoom out of the image).

IE Tab

A handy tool that allows you to view pages as they would appear in Internet Explorer straight from your Firefox browser. You can then easily switch back to Firefox without switching browsers.


With this add-on you can capture screenshots from any browser, not only Firefox. It has the ability to capture the entire web page. No external editor is needed (it has a built-in one already) in order to resize, crop, highlight, blur or erase. You can also add annotations and text with this add-on. Storage is easy in any format. You can also add it to Twitter, Picasa, Facebook, Flickr and so forth. Screenshots can also be printed, emailed and copied to clipboard.