When it comes to web development, there’s no doubt that Firefox is king. What makes it king is the large collection of third-party extensions available for it. These days, just about everyone has heard about Firebug, but what other extensions would you recommend to folks who do web development?


  1. Harry Roberts says:
    June 11th, 2008 at 12:55 pm

    My list would be:
    * YSlow – http://developer.yahoo.com/yslow/
    * Web Developer – https://addons.mozilla.org/en-US/firefox/addon/60
    * MeasureIt – http://www.kevinfreitas.net/extensions/measureit/
    * ColorZilla – http://www.iosart.com/firefox/colorzilla/

    Although I’ve had to cut back on extensions since I migrated to the Firefox 3.0 betas & release candidates.

  2. Eran Galperin says:
    June 11th, 2008 at 12:56 pm

    I use also YSlow for speed optimizations, HTML Tidy for validation and fireshot for screencapturing.

  3. Felix says:
    June 11th, 2008 at 1:11 pm

    Okay, here you go ;)

    HTML Validator

    Live HTTP Headers

    Web Developer


    That’s it.

  4. daniel says:
    June 11th, 2008 at 1:16 pm

    maybe Selenium IDE, it’s quite useful for interface testing

  5. Jake says:
    June 11th, 2008 at 1:30 pm

    I use the following add-ons:
    Firebug (I do not see how any web developer can live without this add-on.)
    Web Developer Toolkit
    Measure It
    IE Tab (PC ONLY)
    HTML Validator
    YSlow – Firebug add-on.
    HTTP Live Headers

  6. Marc Gear says:
    June 11th, 2008 at 1:32 pm

    Firebug, Live HTTP Headers, User Agent Switcher, Web Developer Toolbar, YSlow, MeasureIt and ColorZilla are essential for me, and if you use the related tools Selenium IDE and Zend Studio Toolbar are extreemly handy.

  7. gasper_k says:
    June 11th, 2008 at 1:37 pm

    Here’s my list: Web Developer, Tamper Data, YSlow, FirePHP, User agent switcher, Selenium IDE, Lorem Ipsum content generator, ReloadEvery

  8. Ishino says:
    June 11th, 2008 at 1:48 pm

    Web Developer, FireBug and ChatZilla ^^ so I can have quick access to good rooms on Freenode like #zftalk and #jquery ;)

  9. Thomas Allen says:
    June 11th, 2008 at 1:50 pm

    I use Firebug, Web Developer toolbar, and ColorZilla when doing HTML/CSS/JS web development. I never use these for backend (PHP) development. The toolbar’s great for its ruler, ability to disable CSS/JS, simulate screen size (somewhat) and easily view a page’s stylesheets.

  10. Ian Jenkins says:
    June 11th, 2008 at 1:55 pm

    Perhaps more associated with design, but 2 more…

    - Colorzilla
    - Htmlvalidator

  11. julien-pauli says:
    June 11th, 2008 at 2:52 pm

    Regular expressions tester, Live HTTP Headers, SaveSession, EditCookies, RefSpoof, ZendStudio Toolbar …

  12. Dave Marshall says:
    June 11th, 2008 at 2:54 pm

    I’d install the Web Developer toolbar, some of it’s features have been superceded by firebug, but being able to disable css/javascript/images/cookies, populate forms, use a ruler, quickly outline elements and also send things to the validators is useful.

  13. Joao Prado Maia says:
    June 11th, 2008 at 2:57 pm

    Here’s my:

    Web Developer
    Live HTTP Headers
    HTML Validator
    FirePHP (seems cool too, but still a bit early)
    PrefBar (allows you to disable flash within a Firefox session)
    Duplicate Tab (useful in a few situations)


  14. Matthew Pettitt says:
    June 11th, 2008 at 3:15 pm

    Stylish – like Greasemonkey, but for CSS. Great for seeing if a change will look good and showing it live, without affecting the live site, yet using live data.
    Greasemonkey – similar idea (I don’t actually have it installed at the moment, but have used it to trial ideas on people before)
    Nagios Status – see if your server and sites are healthy, without needing a page open all the time (requires Nagios to be monitoring the server, obviously…)
    Live HTTP Headers – useful for checking dynamic returns and so on

  15. Josh Yudaken says:
    June 11th, 2008 at 3:31 pm

    I use FireBug (obviously), but stangely no-ones mentioned Venkman?

    Its a Mozilla javascript debugger, much better than Firebug’s version

  16. Koji says:
    June 11th, 2008 at 4:21 pm

    My list is simple – WebDeveloper and FireBug. Selenium and YSlow have come in handy as well. I used to use HTML Validator, but I switched to w3c’ service via WebDeveloper.

  17. 131 says:
    June 11th, 2008 at 6:38 pm

    Webdevelopper is…Lame v_v, you just dont need nothing of it.
    Mine are

    - LiveHTTPHeaders
    - Firebug
    - Cache status
    - Timestampdecode
    - Titlebar Tweaks

    And of course

    - chrome://browser/content/preferences/cookies.xul
    - javascript:window.resizeTo(1024,768);

  18. Whisller says:
    June 11th, 2008 at 7:03 pm

    My list ( in random order )
    Web Developer

  19. Dorthe says:
    June 11th, 2008 at 9:03 pm

    The “Firefox Accessibility Extension” gives along other features a report on the accessibility of a page (not that “it does not validate, it’s not accessible at all”-stuff!).

  20. Robin says:
    June 12th, 2008 at 9:01 am

    My sweet list of plugins is more or less already mentioned:
    - firebug: who lives without it?
    - webdeveloper: switching css on/off etc
    - measureIt: it just works
    - colorzilla: again, just works
    - html validator: always handy to see validation results
    - fasterfox: gives me a timer for loading a page…

  21. Robin says:
    June 12th, 2008 at 9:01 am

    ow, and Yslow ofcourse :)

  22. Johny says:
    June 12th, 2008 at 10:12 am

    I just found Selenium IDE which is quite nice for testing but doesn´t satisfy complete yet. otherwise i just have Firebug for debugging ang google toolbar to see pagerank.

  23. Alex@Net says:
    June 13th, 2008 at 8:42 pm

    FireBug is #1
    Rest: WebDeveloper, Google Toolbar, Stop-or-Reload Button, Tab Mix Plus, Locationbar2, Fireshot, Scrapbook, greasemonkey.
    And of course: customize toolbars – http://www.alexatnet.com/node/48
    And a lot of useful bookmarlets: http://www.alexatnet.com/node/85

  24. Lukas says:
    June 14th, 2008 at 6:01 pm

    Will you provide a summary of all of these suggestions?

  25. Alex@Net says:
    June 18th, 2008 at 8:06 pm

    Stuart have done it: http://blog.stuartherbert.com/php/2008/06/16/40-firefox-extensions-every-web-developer-should-check-out/

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