Firefox OS Simulator – previewing version 3.0

Three months ago we were proud to release the 1.0 version of the Firefox OS Simulator. We’ve made a lot of progress since, and version 2.0 came out about a month ago (latest official version). Now, moving forward, we’d like to present and introduce you to a preview of the upcoming 3.0 version!


We discussed whether we should talk about this new version yet, since it’s a bit rough around the edges, but we decided to give it a go for two reasons:

  • We’re Mozilla. We do things in the open, and we share our progress. Because we want you to know what’s going on and to be able to come along with us in the process
  • It gives you an unique opportunity to test it out, give feedback, contribute and much more before it’s released

New features in the preview

We’ve listened to the feedback and have tried to target the most common features being requested and well-needed. New features include:

  • Push to Device
  • Rotation simulation
  • Basic geolocation API simulation
  • Manifest validation
  • Stability fixes for installation and updates to apps
  • Newer versions of the Firefox rendering engine and Gaia (the UI for Firefox OS)

Push to Device

This means that if you have an existing device supporting Firefox OS, connected via USB, you will be able to push apps installed in the Firefox OS Simulator directly to that device.


Please note:

  • Remote debugging has to be enabled on the device, via
    Settings > Device information > More Information > Developer > Remote debugging
  • On Linux (at least Ubuntu), you must create the file /etc/udev/rules.d/51-android.rules as root and then add a manufacturer-specific entry for the device as described by Android’s Setting up a Device for Development. Example for one of our test devices:entry:
    SUBSYSTEM=="usb", ATTR{idVendor}==" 19d2", MODE="0666", GROUP="plugdev"
  • Not complete Windows support yet. Planned to make it into the final release.
  • Make sure you have the latest version of Firefox OS on your device (especially due to recent fixes like bug 842725)


Rotation simulation

There’s now a feature to rotate the simulator, get events and more, to adapt your contents to both portrait and landscape. Supports the mozorientationchange event.


Basic geolocation API simulation

The simulator now also supports geolocation, so you can test it in your app, and read out longitude and latitude values.

Coming soon: an enhancement that lets you specify the geolocation to provide!

Manifest validation

When you add an app to the Firefox OS Simulator, it also does a quick validation of your manifest file for errors and warnings, including problems that prevent installing the app in the Simulator, usage of APIs that the Simulator doesn’t yet simulate (not all APIs in there yet), and missing properties that are required by the Marketplace or devices.


Downloading the preview

We have all the versions of the Firefox OS Simulator on our FTP server, under its working name r2d2b2g. Here are the direct links to the installation files (installs as an extension in Firefox)

Once installed, it will be available in Firefox in the Tools > Web Developer menu:


Give us feedback!

Please let us know in the comments here or by filing a bug. Hopefully you will like the improvements and they will benefit you with developing apps!

Getting started with Firefox OS & building Open Web Apps

To get started, we have had a number of articles here on Mozilla Hacks previously:

Additionally we have some other resources:

About Robert Nyman [Editor emeritus]

Technical Evangelist & Editor of Mozilla Hacks. Gives talks & blogs about HTML5, JavaScript & the Open Web. Robert is a strong believer in HTML5 and the Open Web and has been working since 1999 with Front End development for the web - in Sweden and in New York City. He regularly also blogs at and loves to travel and meet people.

More articles by Robert Nyman [Editor emeritus]…


  1. x I’m tc


    March 13th, 2013 at 09:20

  2. Vincent

    The Linux version of the emulator doesn’t work on the last Ubuntu, using Firefox 19.0.2 and with a precedent version of the emulator installed (then removed and reinstalled, same result).

    March 13th, 2013 at 11:28

    1. Robert Nyman [Editor]

      Please file a bug and we’ll look into it.

      March 13th, 2013 at 12:11

  3. Sankalp

    I am really intrigued by your OS !
    It’s resplendent !
    Do you any plans to launch it in India anytime soon ?

    March 13th, 2013 at 13:36

    1. Robert Nyman [Editor]

      Thanks! We announced the first countries recently. Don’t know at this time which other countries will be covered.

      March 13th, 2013 at 17:01

  4. Igor Costa


    One suggestion to the team, why not adopt Ripple simulator to work together with Firefox OS Apps?

    March 13th, 2013 at 18:13

    1. Robert Nyman [Editor]

      What the Ripple Simulator supports, comparing with Firefox OS Simulator, is, to my knowledge, vastly different. Different products, rendering engines and APIs. It would be interesting to see how it would benefit us to use that.

      March 14th, 2013 at 02:10

  5. Flaki

    Hey! Last time I installed the FFOS Simulator was the very first (1.0) version just as it came out. It was quite a disappointment, using it was like hell on earth on my (yes, pretty outdated) notebook. Nonetheless, I kept the addon disabled for quite some time, thus 2.0 slipped my attention, now just yet I updated to 3.0pre3, and I am honestly, truly *astonished*.

    Yesterday I had the chance to meet the Geekzphone Keon in person and was really, really pleased by the fluidity and speed of the Firefox OS on such an inferior hardware (in terms of recent 4core-several-gigs-of-memory devices out there), and just yet, the simulator is on par with that!

    Excellent work, keep it up!

    March 14th, 2013 at 04:50

    1. Robert Nyman [Editor]

      Thank you. We’re very happy to hear that you think it has improved, and that you are excited about Firefox OS!

      March 14th, 2013 at 05:42

  6. cray


    Which locales are present in image?

    Do you use for Firefox OS translations?

    March 14th, 2013 at 05:05

    1. Myk Melez

      Hi cray,

      Sorry for the delay responding. We just use the localizations already present in the Gaia repository. We don’t add any localizations from other places. However, I recently discussed adding such localizations, and I’m going to investigate the work required to do so. Thus there may be additional localizations in future versions of the Simulator!


      March 18th, 2013 at 23:55

  7. Gsbriele Vidali

    I read that mozilla planned to use snapdragons only, very much like winphone did. Why don’t you consider adopting mediatek cpu too ?

    March 14th, 2013 at 06:48

    1. Robert Nyman [Editor]

      We’re not building the hardware, we’re building the software.

      March 14th, 2013 at 08:48

  8. Philip Casey

    Amazed that the FFOS emulator loaded my music (I know how many tracks I have for the first time) and photos. Couldn’t play the music. It’s really coming on with a whoosh.

    But Bing? Oh dear.

    That prejudice aside, fantastic work, for which thanks. Great to be able to track progress with an emulator.

    March 14th, 2013 at 17:05

    1. Robert Nyman [Editor]

      Thanks, glad you like it!

      March 15th, 2013 at 02:38

  9. nishan

    Hy Robert,
    i read your blog and Hacking Gaia for Firefox OS, part 1.
    i love hacking and wanna make a career in open source …but dont wnna caught like kevin metnick :D,mainly i do red hat linux.. Good to see firefox as OS after using it as browser
    Great Team work …!!
    what will be my next step :) please guide me
    i know html and C..what other programming languages i should learn because i learned everything over the internet and thanks to google for finding your blog.
    nishan limbu
    country – nepal.

    March 16th, 2013 at 07:58

    1. Robert Nyman [Editor]

      I’d recommend to look deeply into HTML5 & JavaScript, since that will be a major part of many things going forward.

      I also think Rebecca has a good outline in A Baseline for Front-End Developers.

      March 18th, 2013 at 02:57

  10. Ken Saunders

    Curious, why not add a beta channel on AMO to (potentially) get more feedback, testers, etc?

    “46,948 users”

    March 17th, 2013 at 00:48

    1. Robert Nyman [Editor]

      It could be an option, going forward. We’ll see what happens!

      March 18th, 2013 at 02:54

  11. Zakir

    Will Firefox OS broswer have full screen browsing meaning when we enter a URL it will show its loading after that it will be full screen no URL on Screen just when we enter URL it shows some andriod browsers have that.

    March 18th, 2013 at 19:06

    1. Robert Nyman [Editor]

      Currently it shows the URL bar at top, but when you scroll down, it gets hidden/scrolled up.

      March 19th, 2013 at 01:06

  12. Carter

    I was on the Mozilla website and noticed that Verizon was not a partner of Firefox OS. Does this mean that it will not be carrying Firefox OS? If so, is there a way that it will carry it in the near future?

    March 19th, 2013 at 15:15

    1. Robert Nyman [Editor]

      Firefox OS devices will initially be released in emerging markets. Countries and partners are listed in the press release. When it comes to possible future partners, nothing more has been announced at this time.

      March 19th, 2013 at 16:23

  13. Dean

    Message says “cannot continue install” because it can’t find a file! I am running Win7x64 and latest FF version…………ideas?

    March 19th, 2013 at 15:29

    1. Robert Nyman [Editor]

      Please file a bug for that.

      March 19th, 2013 at 16:24

      1. gabriele

        What if I find a bug inside the os ?
        While trying latest os emulator I noticed that g+ app opens g+ in full desktop version instead of its mobile counterpart

        March 20th, 2013 at 03:52

        1. Robert Nyman [Editor]

          Please file a bug for that as well – it will be routed accordingly.

          March 20th, 2013 at 06:05

  14. Carter

    when I attempted to play a game in the game apps section, it would either have a massive picture or a tiny one. Not only that, but it also had the pull down thing, ah what’s it called. The notifications window, it got in the way. Is it the actual thing having an issue, or just my emulator? I am running this on Mountain Lion. Thanks!

    March 19th, 2013 at 15:39

    1. Robert Nyman [Editor]

      Nothing is intended to get in the way. Please file a bug to describe it more.

      March 19th, 2013 at 16:25

  15. monster1612

    There should be an option to lock FirefoxOS with a picture password, like Windows 8.

    March 19th, 2013 at 16:08

    1. Robert Nyman [Editor]

      Thanks for the suggestion.

      March 19th, 2013 at 16:25

  16. Zakir

    will Firefox OS have HERE Drive(+), HERE Transit and HERE City Len other than HERE Maps.

    we would love that.

    March 20th, 2013 at 07:44

  17. Daniel

    Is there any way to install this addon in Mozilla Seamonkey? I do not want to have to go and download Firefox just to try Firefox OS.

    March 20th, 2013 at 08:29

    1. Robert Nyman [Editor]

      Not sure Seamonkey is supported.

      March 20th, 2013 at 13:26

  18. zakir

    will Firefox OS have HERE Drive(+), HERE Transit and HERE City Len other than HERE Maps.

    we would love that.

    March 21st, 2013 at 17:28

    1. Robert Nyman [Editor]

      Don’t know at this time, we’ll see.

      March 22nd, 2013 at 02:40

      1. Gabriele

        2d nav has been done already:

        March 22nd, 2013 at 02:59

        1. Robert Nyman [Editor]

          Cool, thanks!

          March 22nd, 2013 at 03:58

        2. Gabriele

          Let me add this solution (iI’m not sure it’s different from scout engine)

          March 22nd, 2013 at 04:06

    2. Gabriele

      By adding 3d html5 layer to this one, here drive will be available for ffos

      March 22nd, 2013 at 02:55

  19. Variya Soft Solutions

    its pleasant!!

    March 24th, 2013 at 09:57

  20. viswaprasath

    Vincent did u problem solved ?
    I too had same problem in this evening. :( :(

    March 25th, 2013 at 09:08

  21. llage

    Fast and fluid… Good job guy ;-)

    March 29th, 2013 at 08:49

    1. Robert Nyman [Editor]


      April 1st, 2013 at 01:04

  22. Anirudha

    on my Win7 64 bit machine if I installed the simulator from then it’s work fine.

    but If I installed from add-ons manager it’s not working after installed.

    March 30th, 2013 at 21:05

    1. Robert Nyman [Editor]

      Interesting. As described in the blog post, please file a bug.

      April 1st, 2013 at 01:05

  23. num

    i dont like this os !!! thinks android always the best

    March 30th, 2013 at 21:50

    1. Robert Nyman [Editor]

      You’re entitled to think that if you want to.

      April 1st, 2013 at 01:05

  24. andres

    Hi robert..personally I found very interesting develop for firefoxOS, I like how integrate html5 and how mozilla bet for javascript and html5…now, personally and this is my opinion, I found the interface design very ugly…looks a bit cheap and worse, like a cheap version for android…html5 is amazing for create interfaces, you can create rich interfaces with animations, transitions and unlimited possibilitis, I know than this phone is for low range phones… but why mozilla doesn’t give a biggest efford in create a better interface?…

    mozilla has any plan from change or update the visual interface or this will be the final look?…how has been received this interface between the press and the people??…

    April 3rd, 2013 at 09:48

    1. Robert Nyman [Editor]

      Glad you like the OS and developing for it!
      When it comes to the UI, the design is described in Gaia Building Blocks. You should ask more in the mailing list for Gaia.

      April 4th, 2013 at 02:28

  25. Gabriele

    What about support for unity engine ? It looks like they’re interested in it

    April 4th, 2013 at 04:07

    1. Robert Nyman [Editor]

      Since everything on the phone is HTML5, it doesn’t sound like a plausible option for Unity.

      April 5th, 2013 at 01:25

      1. gabriele vidali

        So copper/irr-licht is the only viable option to easily build 3d games here atm

        April 5th, 2013 at 01:44

        1. Robert Nyman [Editor]

          Well, I’d say it’s relative to what makes it easy to build 3D games, but since WebGL is in there, there should be a number of options.

          April 5th, 2013 at 02:20

          1. andres

            and the advances in asm.js could be a door for futures 3d game engines inside fOS like the latest example from unreal inside the navigator???…

            April 10th, 2013 at 17:12

          2. Gabriele Vidali

            In regards to unity games, what’s the difference with android?
            FFos : Android = Gaia : Dalvik = html5+js : java
            When games get exported, does gaia require a change of code if compared to android code for the dalvik machine?
            Or html5+js vs java is the main difference between the two os’?

            April 21st, 2013 at 16:52

  26. Caspy7

    I’m frustrated that we can’t install large addons without freezing the browser (this will lead to users hitting “stop” on the script).
    Seems that addon installation should be pushed to a separate thread. Know if this is feasible/on someone’s radar?

    April 20th, 2013 at 13:38

    1. Myk Melez

      Caspy: resolving the problem is feasible, and it’s on our radar. The Simulator issue tracking it is issue #83, and the Firefox bug report is bug 814505. Note that the latest preview build (Windows, Mac, Linux) is 20MB smaller, because we removed non-core apps from Gaia; and we’ll continue slimming it down, which will at least make the problem rarer.

      April 22nd, 2013 at 11:38

      1. Caspy7

        Excellent. Thanks.

        April 22nd, 2013 at 20:16

  27. Robert Nyman [Editor]

    To Gabriele: Firefox OS is not Android + Gaia, it has a small Linux kernel called Gonk, with Gecko and then Gaia on top of it. Best thing is probably to ask the Unity people what they need to do it.

    April 22nd, 2013 at 02:09

  28. Robert Nyman [Editor]

    To andres: Yes, long term asm.js could provide an option for that.

    April 22nd, 2013 at 02:09

Comments are closed for this article.