Mozilla Introduces the First Browser Built For Developers: Firefox Developer Edition

Developers are critical to the continued success of the Web. The content and apps they create compel us to come back to the Web every day, whether on a computer or mobile phone.

In celebration of the 10th anniversary of Firefox, we’re excited to unveil Firefox Developer Edition, the first browser created specifically for developers.

Ten years ago, we built Firefox for early adopters and developers to give them more choice and control. Firefox integrated WebAPIs and Add-ons to enable people to get the most out of the Web. Now we’re giving developers the whole browser as a hard-hat area, allowing us to bring front and center the features most relevant to them. Having a dedicated developer browser means we can tailor the browsing experience to what developers do every day.

Because Firefox is part of an open-source, independent community and not part of a proprietary ecosystem, we’re able to offer features other browsers can’t by applying our tools everywhere the Web goes, regardless of platform or device.

One of the biggest pain points for developers is having to use numerous siloed development environments in order to create engaging content or for targeting different app stores. For these reasons, developers often end up having to bounce between different platforms and browsers, which decreases productivity and causes frustration.

Firefox Developer Edition solves this problem by creating a focal point to streamline your development workflow. It’s a stable developer browser which is not only a powerful authoring tool but also robust enough for everyday browsing. It also adds new features that simplify the process of building for the entire Web, whether targeting mobile or desktop across many different platforms.

If you’re an experienced developer, you’ll already be familiar with the installed tools so you can focus on developing your content or app as soon as you open the browser. There’s no need to download additional plugins or applications to debug mobile devices. If you’re a new Web developer, the streamlined workflow and the fact that everything is already set up and ready to go makes it easier to get started building sophisticated applications.

So what’s under the hood?

The first thing you’ll notice is the distinctive dark design running through the browser. We applied the developer tools theme to the entire browser. It’s trim and sharp and focused on saving space for the content on your screen. It also fits in with the darker look common among creative app development tools.

We’ve also integrated two powerful new features, Valence and WebIDE that improve workflow and help you debug other browsers and apps directly from within Firefox Developer Edition.

Valence (previously called Firefox Tools Adapter) lets you develop and debug your app across multiple browsers and devices by connecting the Firefox dev tools to other major browser engines. Valence also extends the awesome tools we’ve built to debug Firefox OS and Firefox for Android to the other major mobile browsers including Chrome on Android and Safari on iOS. So far these tools include our Inspector, Debugger and Console and Style Editor.

WebIDE allows you to develop, deploy and debug Web apps directly in your browser, or on a Firefox OS device. It lets you create a new Firefox OS app (which is just a web app) from a template, or open up the code of an existing app. From there you can edit the app’s files. It’s one click to run the app in a simulator and one more to debug it with the developer tools.

Firefox Developer Edition also includes all the tools experienced Web developers are familiar with, including:

  • Responsive Design Mode – see how your website or Web app will look on different screen sizes without changing the size of your browser window.
  • Page Inspector– examine the HTML and CSS of any Web page and easily modify the structure and layout of a page.
  • Web Console – see logged information associated with a Web page and use Web Console and interact with a Web page using JavaScript.
  • JavaScript Debugger – step through JavaScript code and examine or modify its state to help track down bugs.
  • Network Monitor – see all the network requests your browser makes, how long each request takes and details of each request.
  • Style Editor – view and edit CSS styles associated with a Web page, create new ones and apply existing CSS stylesheets to any page.
  • Web Audio Editor – inspect and interact with Web Audio API in real time to ensure that all audio nodes are connected in the way you expect.

Give it a try and let us know what you think. We’re keen to hear your feedback.

More Information:

About Dave Camp

Dave Camp is Director of Engineering for Firefox at Mozilla.

More articles by Dave Camp…


  1. Dan Neame

    Can’t wait to give it a go!

    November 10th, 2014 at 07:16

  2. Cedric

    This separate build will adress best the needs of developpers.
    Please move out developper features from the mainline Firefox, it’s gotten WAY too bloated for a browser, at the detriment of features actually useful to users.

    November 10th, 2014 at 07:43

  3. ashnur

    Firefox for a big number of js devs – those who use browserify (or an alt-js language) is almost completely unusable because of the lack of source map support in the console. Given that, this “dev version” is a bad joke.

    p.s. oh, and I bet that I still can’t have bookmarklets to download content from the web.

    November 10th, 2014 at 07:49

  4. fayssal

    Thanks, Mozilla always the best ;-)

    November 10th, 2014 at 07:55

  5. Sandeep Maity

    Thank Dave…….

    November 10th, 2014 at 07:58

  6. Firefoxxy

    Your first video on this page doesn’t play on Firefox (Mac).

    November 10th, 2014 at 07:59

  7. Gaurav

    Waaaoo!! Great browser for developers
    #fx10 #mozlove #happybirthdayfirefox

    November 10th, 2014 at 08:02

  8. pskept

    I’m confused about how this will play into the standard ff edition since this has replaced aurora. Will all of the changes in the developer edition make it down to the standard edition? What about the dark look and feel?

    November 10th, 2014 at 08:03

    1. Dan Callahan

      Most features will make it into standard Firefox, but many aspects of the developer edition, like the new theme, are disabled by default unless #ifdef MOZ_DEV_EDITION during build. E.g.,

      November 12th, 2014 at 09:32

  9. sally

    Is this just Aurora under the hood

    November 10th, 2014 at 08:03

  10. Sekander

    Why does it seems to me that all the features are already present in 33. I could not find nothing new or extra in the dev edition :3

    November 10th, 2014 at 08:10

  11. Patrick H. Lauke

    I ranted about this on Twitter already, but: it would have been nice to clarify in this post that Firefox Developer Edition *replaces* Firefox Aurora (or rather, it’s the new name for what used to be Aurora)

    November 10th, 2014 at 08:17

    1. Supermighty

      I guess Mozilla feels the dev tools are mature enough in, what was, Aurora; and they want to get developers using the new tools sooner. Which, really, will lead to more tool feedback, which will lead to better tools.

      November 10th, 2014 at 08:20

  12. Supermighty

    I have always loved the tools Firefox has for developers. I think think is a step in the right direction for tooling.

    November 10th, 2014 at 08:18

  13. lejenome

    when these additional changes to Aurora (browser.devedition.*) will land to Nightly as default? or they will be just enabled for Aurora version?

    November 10th, 2014 at 08:28

  14. Ivan

    I’m already using Aurora (and update daily), so I didn’t see so much difference…

    I didn’t like the squared tabs, but ‘Carbon Theme’ + ‘Light Theme on FDevTools’ looks perfect… Thanks!

    I thought the ‘dev profile’ is unnecessary, but making possible using my own current personal profile was a good idea (I’m a developer and a normal user at the same time and I don’t need 2 instances of FF :) Thanks again…

    The ‘Developer tools tab button’ looks very useful…

    November 10th, 2014 at 08:30

  15. sally

    Is there a FreeBSD release of this version?

    November 10th, 2014 at 08:54

  16. Resuna

    How about a “firefox sysadmins edition”? Or at least fixing the bugs that keep sysadmins from being able to use Firefox, like

    November 10th, 2014 at 09:05

  17. Brian LePore

    First, I am happy about this. Nice little tweak to the browser. Was familiar to my main browser set up already, though I added a user-agent switcher to it.

    Will Valence ever allow debugging of iOS from Windows? I suspect not, but the fact that it can from Linux surprised me so I thought we might have options beyond just OS X for debugging.

    Still sad to see the Responsive Design Mode hasn’t matured much since it first emerged. Needing to go to about:config to add new dimensions is a cheat. And it really needs to let you modify the device pixel ratio like you can in Chrome.

    November 10th, 2014 at 09:18

    1. Brian Grinstead

      Regarding Responsive Design Mode, we are working on updates at

      Feel free to subscribe to that bug and/or file new ones and mark them as blocking 1028905. Alternatively, please submit any ideas to uservoice here:

      November 10th, 2014 at 10:32

  18. Neil Stansbury

    It’s a shame it wasn’t made clearer that Aurora was just being renamed.

    I’m not why you’d make the entire browser theme the same as the dark Dev Tools theme. IMO it’s a visually poor theme anyway, but applying it globally means Mac users can’t drag the browser anymore as there is no space above the tabs, so it reduces usability too.

    To be honest, I feel a rather underwhelmed by the whole thing. There’s no new easy access to these tools, they’re still under 2 menu levels with no consistent UI joining them all together – a simple Dev Tools sidebar would have been an improvement on accessing and switching between them.

    There is definitely a need for a vision for a consolidated toolset, but so far this feels just like a really weak re-branding exercise instead.

    November 10th, 2014 at 09:29

  19. S. Squid

    Does that mean that you will remove the developers console from normal firefox? Having it installed perhaps contains the risk of noobs convinced on facebook to enter commands they don’t know in order to, as they think, “hack someone” while themselves giving access. But still removing it would make the web less open and would contradict, as I read it, point 5 of the mozilla manifesto.

    November 10th, 2014 at 09:45

  20. Ivan

    “Needing to go to about:config to add new dimensions is a cheat.”

    I can add new dimensions just typing on ‘dimension edit’ (example 123×456) and ENTER and then clicking on ‘Add Preset’…

    A friend of mine show me that Chrome has some smartphones screens size… It would be great to have this on FF…

    November 10th, 2014 at 10:09

  21. Matěj Cepl

    Why in the world I use browser created by people who are so [REDACTED] that they cannot develop video presentation in format which they would actually support (yes, I am on 31ESR)? Do I have to download Chrome just to see videos by Mozilla? Guys!

    November 10th, 2014 at 10:18

    1. Nick Desaulniers

      Sorry about that, here are some webm transcodings:

      November 10th, 2014 at 14:38

  22. ttopkcaj


    that that update to FDE replaced my Aurora, with all my AddOns, bookmarks and saved sessions. :_( Any possibility to go back???

    November 10th, 2014 at 10:35

    1. Dan Callahan

      Sure, just uncheck “Allow Firefox Developer Edition and Firefox to run at the same time” in preferences to default back to your old profile, instead of the new dev edition profile.

      November 12th, 2014 at 09:40

  23. Kosyne

    Looks good, but the new titlebar’s theme does not play nice with custom windows themes:

    November 10th, 2014 at 10:40

  24. Samarthwiz

    How would we change the browser’s interface language?

    November 10th, 2014 at 11:12

  25. kaushik vira

    This is really Bad Ass… Really loved it.

    November 10th, 2014 at 11:16

  26. Alex Bell

    Great to see all the activity in this area.

    One nit: Please bundle a high contrast black text on white (or nearly white) theme. I hate the black theme. It’s a personal preference, of course, but it’s also a preference based on years of legibility research showing black on white letterforms are more legible than white on black. And I don’t want to crawl through thousands of idiosyncratic “flavored” themes just to get to back to something vanilla. Let people who want rounded tabs and black on white(ish) go back with one click, please. Hate to say it, but Chrome Dev Tools got the default theming options exactly right here.

    “Space Fantasy” and “Linen Light” are your recommended alternative themes? This is questionable developer marketing.

    November 10th, 2014 at 11:48

    1. Kumar McMillan

      It is bundled. Click ‘customize’ on the browser title bar menu (to the right of the URL bar). In there you’ll see a Theme button. From there you can choose the Simple Fox theme which is the one you are looking for.

      November 10th, 2014 at 12:16

  27. Mark

    FF getting better and better :)

    But still, the developer tools are lacking usability and functions. Accept that the competitor has a better devtools and that you should catch up. If you keep avoiding accepting Chrome as a superior product for developers because of some ideology, you will keep trying to make your devtools some magical weird stuff just because you don’t want to make something similar to it. It’s just a tool, accept it, make developers life better, move on.

    November 10th, 2014 at 12:19

  28. Dane MacMillan

    This is really minor. The extra screen real-estate introduced from the new theme is great. Can you possibly reduce the vertical padding on the tabs also? Can you (on OSX) un-round the bookmarks in the bookmarks toolbar, and reduce their horizontal padding, so more bookmarks can be squeezed in? I feel like some of the design choices are a direct descendent of “small icon mode,” which probably only a small number of people (developers?) cared about, which I’m completely in favour. Ultimately, these are unimportant nitpicks, which detract nothing from the browser.

    I have some questions about the Developer Edition in general, though. How do you figure this browser will distinguish itself from Nightly, which I know many developers are already using? Given that Nightly is a full release ahead of the Developer Edition, what do you think will compel those users to migrate to this one? I specifically use Nightly to get all the latest changes in the Developer Tools, and secondarily to test new JavaScript APIs and CSS candy. There’s also the added benefit of being able to catch bugs and report them as they are introduced. Will the Developer Edition get those Developer Tool updates at the same time as Nightly, or will it need to wait a full release cycle to get them?

    November 10th, 2014 at 12:49

    1. Jeff Griffiths

      We got the padding down to a level that we were comfortable – we now have a few pixels less than chrome in terms of height ( on OS X ). We have had comments on tightening up padding horizontally from a few channels, and it’s worth considering given that we’re targeting developers who tend to have many many more open tabs than regular users.

      With respect to your question about Nightly, I think we have some room to differentiate via customizations that simply can’t happen on nightly. This is just the start.

      November 10th, 2014 at 15:21

      1. Michał Gołębiowski

        One thing that bothers me is that the Developer Edition will get improvements/bug fixes to the browser & dev tools up to 6 weeks after release. That’s why developers will have a hard time choosing one over another.

        Did you look at Chrome’s release schedule? They also have 4 channels but Canary & dev are on the same major version most of the time, dev is just a few days behind. Only a few days before the release Canary gets a bump and dev stays on the major it was so the window between Canary & dev is always narrow.

        Any chance Firefox Developer Edition could behave more like the dev channel of Chrome? It would also make the whole release cycle shorter.

        November 11th, 2014 at 07:45

  29. Drake Logan

    So, I downloaded the update a few hours ago, thinking it was just another minor change, security fixes that I’d never actually see in a log that I’d be able to find. Didn’t restart immediately, had stuff to do, come back a few hours later and Aurora is replaced by Developer Edition and I don’t have any of my folders-and-folders of bookmarks (and I’ve been working on it and through it for years, that was terrifying).

    Went to check and see what happened, downloaded the Firefox Beta while searching, and my settings and bookmarks are back in place there, then found this. Panic fading, plotting how to try using the Developer’s Edition now.

    But seriously, that was kind of scary.

    November 10th, 2014 at 13:10

  30. Sergio

    So, will the developer edition be able to edit local files and also map pages in a local server to local files? The idea is to save changes made with the Inspector directly to original files.

    November 10th, 2014 at 13:53

  31. Alex Bell

    @Kumar Sorry, I’m not seeing “Simple Fox” as bundled. I go to through Menu>Customize>Themes button. The themes that show there are the default black one and some of the crummy ones I named . When I search for “Simple Fox” as a theme using “Get More Themes” I see a theme with that name by AMVPlaya from 2009. It’s… horrific :) Surely that’s not what you mean? Can you post a link to the theme you’re talking about?

    November 10th, 2014 at 16:23

    1. Loweis

      @Alex Bell: just go to options of Developer Tools and coose “Light Theme”. The whole browser theme will adjust accordingly.

      @Mozilla: Great job, happy developer over here!

      November 11th, 2014 at 00:35

    2. Rimas

      There is a toggle button next to the theme chooser drop-down, that says “Use Firefox Developer Edition Theme”. I suppose you just want to toggle it off.

      November 11th, 2014 at 02:02

  32. Scott Sexton

    Just updated to 35.0a2 (2014-11-10) and now all of my bookmarks are missing.

    Did this happen to anyone else?

    November 10th, 2014 at 16:54

  33. Arno

    What about Aurora ? yesterday I was using an “alpha” version of Firefox which can have bugs, and today I have “a stable developer browser” with a new interface and all my preferences gone (hopefully it is possible to get the back but it is hard to find how…). Not everyone was aware of this change, are you kidding me ?

    November 10th, 2014 at 17:02

  34. Corvin

    With this update, I lost everything. All my cookies, all by bookmarks, all saved data.
    Forefox now acts likle a completely fresh install.
    Is there anything I can do to get my data back?
    It would have been nice to opt out of this to save my data before the update.

    November 10th, 2014 at 17:46

    1. Michał Gołębiowski

      Just disable the “Allow Firefox Developer Edition and Firefox to run at the same time” checkbox in preferences and restart the browser.

      Your profile is there, it just stopped being used in favor of the new default separate profile. You can restore the previous situation.

      November 11th, 2014 at 07:50

    2. Corvin

      So, update. I rolled the program back to a previous version, ran that previous version, and backed up all my bookmarks.
      If you have a “previous version” this’ll work for anyone else with this issue I’d bet.

      November 11th, 2014 at 10:10

  35. James

    Firefox Developers addition just installed from Aurora and it changed my layout and got rid of every bookmark and plugin wtf some one tell me how to make it like it was I like the black but could have at least left the layout i had.

    November 10th, 2014 at 18:46

  36. Stephan

    Sync FF on Ubuntu 14.04 doesn’t seem to work. Can someone confirm?

    (I forgot my password and reset it with the link a got sent to my email. When clicking the sync button on the menu nothing happens.)

    November 10th, 2014 at 19:31

  37. gokul

    Cool!. Going to try it. Go go go

    November 10th, 2014 at 19:42

  38. Karl

    LOVE the Web Audio Inspector. Would be awesome if you could jump from a node in the routing matrix to corresponding lines of code in the JS debugger.

    Responsive Mode is cool- can’t tell, but does it do user agent spoofing, like Chrome’s mobile device mode does?

    November 10th, 2014 at 20:48

  39. Brian

    Woke up this morning started Firefox Aurora and it updates to developer edition.

    And there went all my bookmarks…

    Thnxs for the warning mozilla

    November 10th, 2014 at 22:17

    1. Dan Callahan

      Dev Edition uses a fresh profile by default so it can run side-by-side with normal firefox. Your old profile is still there. You can get back to it by running normal Firefox, or by unchecking “Allow Firefox Developer Edition and Firefox to run at the same time” in preferences.

      November 12th, 2014 at 09:50

  40. chivorotkiv

    How to report a bug?

    November 10th, 2014 at 22:37

  41. Iman

    Don’t forget to add the zencoding and auto complete features to the next version.
    Thanks, I like the new Firefox.

    November 10th, 2014 at 23:07

  42. Abhishek Anne

    Symentec Protection blocking installer file…..

    November 10th, 2014 at 23:32

  43. Andrew

    I hope it plays nicely around regular Firefox

    November 11th, 2014 at 02:03

  44. Anonymous

    Great, now all that’s missing is a Firefox built for users.

    November 11th, 2014 at 03:48

  45. Eka

    i like it :)

    November 11th, 2014 at 03:54

  46. Stephen Spencer

    To get your data back, just untick “Allow Firefox Developer Edition and Firefox to run at the same time” – it’ll revert to using your user profile rather than the (newly-created) segregated FDE one.

    November 11th, 2014 at 04:00

  47. valu

    FF comeback. Lately ˛I was using it less and less but with this great piece of software I’m coming back.

    November 11th, 2014 at 04:04

  48. Sven W.

    Can i use it in german?

    November 11th, 2014 at 04:12

  49. Vignesh

    Whats the process change involved with this new edition?. Will the new features land in Nightly and Dev edition at the same time?. Can you guys elaborate?.

    November 11th, 2014 at 05:05

  50. Stuart

    The contempt shown by Mozilla to its existing Aurora-channel users is astonishing.

    This change has been tremendously disruptive, occurred silently with no notice or apology, and there is no way to revert all of the damage it has caused.

    November 11th, 2014 at 06:18

    1. Michał Gołębiowski

      There is a way; see

      November 11th, 2014 at 07:54

    2. Paul

      As the user literally 4 posts above you said, just untick the box in the settings. Or use Sync. For the record, I quite like it, but I don’t see what it has that nightly doesn’t.

      November 11th, 2014 at 08:25

  51. Emil

    I need a Portable version of Developer edition – this way I get to use it without breaking company software policy…
    Please has this been packaged as Portable?

    November 11th, 2014 at 06:51

    1. Don Coleman

      There is Aurora (Firefox Developer Edition) for Android:

      November 11th, 2014 at 09:59

    2. Erkin Alp Güney

      It is possible but you would lose a part of your debugging abilities. Better ask your boss for a special permission.

      November 11th, 2014 at 10:05

    3. V

      There’s a zip on
      it’ll probably try to create/use a profile in the customary locations, but you can probably find how to change the profile path to a usb stick or use Sync to transfer your settings
      these might help with that:

      November 21st, 2014 at 23:27

  52. Robert

    Looks great but it it does not seem to work with Polymer. My application works perfect on chrome but does not load at all in Firefox DE. It doesn’t render anything at all insde the tag.

    November 11th, 2014 at 07:01

  53. AG

    after install it crashes all the time, can’t get it to run.

    November 11th, 2014 at 08:43

    1. April Morone

      Yes, but how did you install it? If through the ppa repository through linux Terminal, you might have better luck with it.

      November 29th, 2014 at 00:56

  54. Robert

    The moment Mozilla introduced the Asstralis inteface, I stopped using their bloatware.

    November 11th, 2014 at 09:23

    1. Googum

      Simbly epic! :^)

      November 12th, 2014 at 09:06

  55. Android App Review

    We were wondering when can we except the mini version of Firefox like all others ?

    November 11th, 2014 at 09:39

  56. Mats

    I lost my “developer theme” when I restarted the browser. I lost all borders. :(

    November 11th, 2014 at 10:45

    1. Albert

      Had the same experience. Maybe you installed Firebug v3 along with it. That comes with it’s own theme, which you can change back in DevTools > Settings > Themes

      Hope that helps :)

      November 13th, 2014 at 03:53

      1. Mats

        You’re right, that did help. Thanks. :)

        November 13th, 2014 at 04:44

        1. Albert

          fyi: the fb theme seems to get fixed with Firebug 3 alpha 3 –

          just found it in the list of known issues:

          November 14th, 2014 at 17:43

          1. samy

            Dear Albert,

            I want to develop a specific feature for the web browsers including chrome and firefox. I am new to this area, but have some good ideas as to what features should be available on a standard browser,
            Could you please suggest me how to achieve it, I dont know web programmaing, Would really appreciate your help.

            December 1st, 2014 at 14:53

        2. kushagra

          It is not working for me..even i uninstalled firebug. how can get dark theme back.. ??

          November 16th, 2014 at 21:49

          1. Albert

            … and you tried switching it via DevTools > Settings > Themes ?

            November 18th, 2014 at 20:41

  57. Ed

    A few things that hit me right off in the debugger:

    1) It cannot have tabs for the files you are working with in a debug session. When you have dozens or hundreds of JS files in your project, this makes it very difficult to work with just 2, 3, or 4 of those files in a debug session.

    2) The same kind of thing applies to the breakpoints being listed under the files in the side list. When you have breakpoints set in a large list of files, it would be really annoying to use that debugger for toggling those breakpoints on and off. Chrome puts the breakpoints in its own section so they are all together and easy to switch to when debugging.

    3) The visual stack path at the top is pretty much a waste since you have the call stack tab that shows the same type of information. Using that space to have the files on tabs that you are working with would be a far more useful feature.

    These two items alone make it a non-starter in comparison to using Chrome for a large application debugging.

    November 11th, 2014 at 11:26

  58. dav

    Full Offline installer? Localized versions?

    November 11th, 2014 at 11:44

    1. Stephen Spencer

      The full array of installers are here:

      November 12th, 2014 at 02:15

  59. Steven Roussey

    Does this have e10s enabled?

    November 11th, 2014 at 11:47

  60. Tad Scsi


    One can no longer expect a browser to open to device screen resolution as always was the case before? Now we get an aborted 1536 or whatever width on a 1920 display?

    Kinda takes planning graphics OUT OF THE PICTURE – so to speak. Graphics that look great on ANY OTHER BROWSER including regular Firefox, look like hell in default ‘browser’ resolution.

    The responsive tool do nothing to help. Zooming back out two steps, restores the 1920. WHY? WHY are you screwing with crap like that?

    November 11th, 2014 at 20:30

  61. Userbard

    Trying to make the jump from google chrome/chromium since I really want to support Mozilla.

    Couple of issues hangups so far, but I am finding the new Developer browser reasonably comfortable to work with. – (Unix – Elementary OS)

    1) Inspect element currently does not inspect the element. It only opens the inspector I have to then use the ‘PIck and element from the page’ look to actually inspect the element I want.

    2) Would be great if I could drag an element to a different place in the inspector. eg: Move an element that is inside a div outside of that div by dragging it.

    3) Its a pain having to edit html when I want to add a class/id/data attribute to an element on the page. Can there be a ‘Add Attribute’ option added to the inspector right click?

    November 12th, 2014 at 14:45

    1. Brian Grinstead

      Userbard, thanks for trying it out and sending over the feedback!

      1) Sorry about that, it’s a known bug that has a fix but may take a couple of days to get uplifted to DevEdition
      2) There is a bug opened that has some recent activity for drag/dropping nodes in the inspector: Hope we will be seeing this soon also.
      3) You can click on the closing bracket of the open tag which will create a space to add a blank attribute by pressing enter or double clicking on it. Alternatively, start editing an existing selector and just add the new attribute at the end of it.

      Definitely keep in touch with other issues that you bump into as you make the jump. The best way would be to contact @FirefoxDevTools on twitter or ask in the #devtools channel on mozilla IRC.

      November 12th, 2014 at 15:08

  62. Mark

    Great work. I have been using developer version since it came out. I like the new flat theme and that you gave users a choice of light or dark theme. quite spiffy. I find the network tab very helpful.

    November 12th, 2014 at 16:00

  63. Hiram

    Loving the interface so far! Noticed the inspect element issue and glad a fix is being worked on.

    The main issue for me (that is ultimately making the decision to consider actively using it very hard) is performance. Getting a lot of cpu spikes pushing over 100%. Mostly when using the developer tools, or viewing a website using any kind of CSS animation.

    November 12th, 2014 at 16:14

  64. mark bokil

    Just want to remind folks if you are not into the dark theme you can change it to light theme under Toolbox Options (panel with the console).

    November 13th, 2014 at 08:53

  65. krastley

    Like it, use it, work with it. Thank you, Mozilla! Love dark look and feel. Just beside mentioned bug with DOM inspector, I have another one with eyedropper: Whenever I try to use it, coursor becomes invisible. Tool itself works, I was able to click on something blindly and paste grabbed value. But that’s far from being usable :) I’m using linux with Xfce.

    November 13th, 2014 at 09:29

    1. Brian Grinstead

      krastley, thanks for the kind words. Regarding your issue with the eyedropper, I’m guessing that is the same as, which seems to be some underlying issue with the XUL panels. If you think that’s the same thing you are seeing would you mind commenting in that bug with your platform details including the window manager you are using?

      November 13th, 2014 at 16:59

  66. Caryn Merritt

    I would like to know how to keep Firefox for my opening page were his tail swirls around the world and his body.When I connect to Firefox and the internet the Firefox comes on with a swirl. I think that is cute and exciting. How do I keep that? Please let me know. Sincerely, Caryn Merritt email:

    November 13th, 2014 at 11:22

  67. Maurizio

    I have been using the program for a couple of days and so far it sounds great.
    The dark theme is fantastic, and you have a lot of information and tools for any task at hand!
    Just a single suggestion at a glance: using the element picker tool, it would be nice if the Web developer tools window came back on top after clicking with the mouse on the object to be examined.
    Anyway, a great job. Thank you!

    November 13th, 2014 at 13:56

  68. Retina

    Opera released their version called Opera Emulator in 2012

    November 14th, 2014 at 05:14

  69. Toby Mathews

    Hi there,

    I also think this is a great idea. In addition to the inspect element issue, I’m getting sporadic issues with display, where parts of web pages disappear, or obscured by large blocks of colour. It’s not consistent, but it happens a fair but (it’s actually happening right now, I’m getting intermittent occurrences of blocks of background colour displaying on this white text field I’m typing into!).


    November 14th, 2014 at 10:10

  70. Matt McFarland

    This is great. But it’s too bad Inspect element does not work properly. It does not select elements at all, just – tested with my colleagues as well. This glaring bug, wow. Not sure how this passed QA.

    November 14th, 2014 at 14:52

    1. Mark

      Inspect element button has been fixed. I am using Nov. 16th build and it is working fine.

      November 16th, 2014 at 09:49

  71. Arron Bates

    Sitting doing nothing with the network panel open, and it’s chewing 56% CPU on one of the cores. regardless of how long I wait, it doesn’t stop pounding on the CPU. uncool, especially for working on a laptop when every other browser + network monitor (even original FF and httpFox) ticks over at a very low pace.

    November 15th, 2014 at 15:48

  72. Kyl

    Since this is the developer addition…

    One nice feature would be when developing angular apps and the angular errors pop up in the console with a url…those urls are clickable and take you to the webpage (just like chrome does). Right now you can hardly copy the urls.

    November 15th, 2014 at 15:55

  73. Antonio Sánchez


    November 16th, 2014 at 09:44

  74. Paul

    You can enable the dev theme in at least Nightly (don’t know about the other versions) by settint the about:config option “browser.devedition.theme.enabled” to true.

    November 17th, 2014 at 08:47

    1. Mark

      Or if you are a GUI person you can just open Customize and click the button. :)

      November 17th, 2014 at 14:37

      1. Paul

        Huh. Didn’t see that. And I thought I had found something hidden.

        November 20th, 2014 at 14:02

      2. Paul

        BTW, I was talking about in Nightly, not developer edition.

        November 23rd, 2014 at 18:56

  75. Bang Roy Han

    this COOL job for me, may can add facility like
    – disable / enable block (div) with some setting [not on inspect element, but on like button]
    – force enable right click and force enable keyboard, when site use some javascript or css disable select, right click, disable keyboard.

    November 17th, 2014 at 11:22

  76. Robin

    Really Really excited about it.
    Gave it a go and its really fast too. Will be learning more tips and tricks soon.

    November 17th, 2014 at 15:12

  77. Adam

    The search functionality in inspector doesnt work..

    Im also no sure where to even post bugs for this version..

    Needs a lot of work.. This is ALPHA ?

    November 18th, 2014 at 10:34

  78. Travis

    Could someone at Mozilla please found out what the background track for that teaser trailer was? It’s amazing!

    November 18th, 2014 at 20:07

  79. Juan Sebastian Ruiz Casas


    My name is Juan Sebastian Ruiz Casas. Im studing desing web with CSS and Javascript de WebApps, incl. móviles FirefoxOS, but dont understand totally.
    I do want understand the desing. Can you help me?

    November 23rd, 2014 at 20:26

  80. MattK

    My main problem with it is an aesthetic one. The Inspector stacks the HTML and CSS windows horizontally when under 700px wide, but automatically jumps them to a side-by-side view once the inspector gets to over 700px wide.

    I can’t find a way to keep the 2 windows stacked one of top of the other. This makes either one or both of the window practically useless to me.

    It looks like I’m staying with regular Firefox with Firebug for the time being.

    November 23rd, 2014 at 21:22

  81. Alex

    I’m new to the developing world, but the Firefox Developers Editions seems to be very user friendly. Glad to start learning with it!

    November 23rd, 2014 at 22:36

  82. Jasa Pembuatan Software

    Im a Programmer at Jogja Software, im try to develop a ads on for Mozilla.

    November 27th, 2014 at 13:12

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