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  • This is a list of Firefox Extensions for Web Designers and Web Developers.

    Firefox Extensions


    Web Developer

    Adds a menu and a toolbar with various web developer tools.


    Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse.


    Python logging support for web developers.


    Symfony Web Debug Toolbar for Firebug. Seamless Symfony debugging inside the popular Firebug.

    JavaScript Debugger

    Venkman is the code name for Mozilla’s JavaScript Debugger. Venkman aims to provide a powerful JavaScript debugging environment for Mozilla based browsers.

    Live HTTP Headers

    View HTTP headers of a page and while browsing.

    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.

    SQL Injection

    It makes easier to test and identify SQL injection vulnerabilities in web pages.


    Console2 replaces the JavaScript Console with what could be the next generation Error Console.

    Managing Cookies


    Firecookie is an extension for Firebug that makes possible to view and manage cookies in your browser.


    CookiePie enables you to maintain different cookies storage in different tabs and windows.

    Viewing and Editing Source Code


    Javascript syntax highlighting for Firebug.

    Inline Code Finder

    Inline Code Finder is an add-on to Firebug, to be able to find HTML elements.


    Get the feel of Dreamweaver in a Firefox extension. Edit your documents right next to your web pages as you surf.


    Chickenfoot is a Firefox extension that puts a programming environment in the browser’s sidebar so you can write scripts to manipulate web pages and automate web browsing.

    XPath Checker

    An interactive editor for XPath expressions.


    Stylesheet modifier in the Sidebar.


    ViewSourceWith allows users to open (and in some cases edit) page source with external applications.


    LiveCoder extends Firebug by allowing developers to look at the Firefox chrome. It’s especially valuable to developers building add-ons.


    A simple CSS property viewer.


    Platypus is a Firefox extension which lets you modify a Web page from your browser.


    Lets you customise your Mozillan Application.


    Adds toolbar button and context menus for invoking the DOM Inspector (DOMi) for either chrome or content elements.

    DOM Inspector

    DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application.

    Design Process


    Advanced Eyedropper, ColorPicker, Page Zoomer and other goodies.


    Draw out a ruler to get the pixel width and height of any elements on a webpage.


    GridFox is a Firefox extension that overlays a grid on any website.

    Pixel Perfect

    Pixel Perfect is a Firefox/Firebug extension that allows web developers and designers to easily overlay a web composition over top of the developed HTML.


    Pencil is a Firefox add-on to do GUI prototyping and simple sketching.


    See the tags on a page without viewing the sourcecode.

    Window Resizer

    Resize your browser to various standard resolution sizes.


    Fangs is a Mozilla Firefox extension that displays a text representation of a web page similar to how a screen reader would read it.

    Colour Contrast Analyser

    A colour contrast analyser that examines the foreground and background colours of text nodes, and provides a report to see if they are correct according to AERT and WCAG’s luminosity colour contrast algorithm.

    Adsense Preview

    Preview the Google ads that may show on any web page.

    Image Zoom

    Adds zoom functionality for images.

    Testing Cross-Browser Compatibility

    IE View Lite

    This is a cut down version of IE View by Paul Roub, which is 47.4 KB. All the same UI and features are there.


    OperaView extension makes that process easier by adding item View This Page in Opera to the page context menu and a button to the toolbar and item Open Link Target in Opera to the link context menu.

    Safari View Win

    Adds a context menu entry to open the currently viewed web page in Safari on Windows.

    User Agent Switcher

    Adds a menu and a toolbar button to switch the user agent of the browser.



    Seoquake is a Mozilla Firefox extension aimed primarily at helping web masters who deal with search engine optimization and internet promotion of web sites.

    RankQuest SEO Toolbar

    RankQuest SEO(Search Engine Optimization) Toolbar provides you quick access to more than 30 intuitive SEO tools.

    Link Checkers


    FireSpider is a an extension for Firebug that can help you find broken or misleading urls and optimize your web page for search engines.


    Check the validity of links on any webpage.


    HTML Validator

    HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla.

    CSS Validator

    Validates a page using the W3C CSS Validator.

    RSS Validator

    Validates a page using the W3C RSS Validator.


    One Click Validator. Provides you a button to validate a page.

    Monitoring and Analyzing Performance


    YSlow analyzes web pages and tells you why they’re slow based on Yahoo’s rules for high performance web sites.


    HttpFox monitors and analyzes all incoming and outgoing HTTP traffic between the browser and the web servers.


    It tracks how long it takes to complete displaying the page and much more.


    It adds an additional panel to Firebug that provides a visual view of the Javascript time measurements captured by Jiffy-Web.



    It will save what you can see in the window, the entire page, just a selection, a particular frame. Basically it saves webpages as images.


    Capture an entire web page or part of a web page and save it as an image.


    FireShot is a Firefox extension that creates screenshots of web pages.

    Automating Tasks


    Automate Firefox. Record and replay repetitious work.


    A webtest tool. Capture, replay, edit, report, automate.


    DéjàClick is a web recorder and Super Bookmark utility designed exclusively for Firefox. You can record and bookmark your browser activities, then with a single click, replay the entire sequence all over again.

    Common Tools

    Extended Statubar

    A Statusbar with speed, percentage, time and loaded size (similar to Opera’s one).

    Tab Mix Plus

    Tab Mix Plus enhances Firefox’s tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more.


    The most beautiful yet the simplest add-on that makes a strong colorful appeal.

    Split Browser

    This splits the content area of the browser window as you like.


    Allows you to customize the way a webpage displays using small bits of JavaScript.


    FireFTP is a free, secure, cross-platform FTP client for Mozilla Firefox which provides easy and intuitive access to FTP servers.


    Dummy Lipsum

    Generate “Lorem Ipsum” dummy text

    Autofill Forms

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

    Custom Button2

    The Custom Buttons2 Firefox extension provides the code base support necessary to create, maintain, import, and export custom toolbar buttons.

    OutWit Images

    OutWit Images allows users to quickly navigate through Web pages and search engine results to harvest countless images automatically or manually.

    SQLite Manager

    Manage any SQLite database on your computer.

    Plain Old Webserver

    Turn the web on its head with the Plain Old Webserver (POW), which adds a server to your browser.

    Server Switcher

    Easily switch between your development and live servers.


    FoxyProxy is an advanced proxy management tool that completely replaces Firefox’s limited proxying capabilities.


    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.

    Piggy Bank

    Piggy Bank is a Firefox extension that turns your browser into a mashup platform, by allowing you to extract data from different web sites and mix them together.

    Regular Expressions Tester

    Testing Tool for regular expressions with color highlighting.

One Comment on “A Complete List Of Firefox Extensions For Web Developers”

  1. Roman (January 14th, 2010, 1:32 am)


    Thanks a lot for our great list! I recently uploaded new addon for Firebug – FireLinkReport (, would be very grateful if you could add it to the list.

    Thank you,

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