Firefox OS Simulator 1.0 is here!

Three weeks back, we introduced the Firefox OS Simulator, a tool that allows web developers to try out their apps in Firefox OS from the comfort of their current Windows/Mac/Linux computers. We’ve seen a number of comments from people who used the Simulator as an easy way to get a peek at Firefox OS today, which is fine, too.

Since that last blog post, the team has been squashing bugs to get the Simulator ready for more use. Linux users in particular will be happy to know that the current release will run on many more systems. With today’s 1.0 release, we hope to see many more users!


We’re leaving the “Preview” tag on the Simulator for now, both because the Simulator is new and because Firefox OS itself is still in development. This is a perfect time to create apps that work on Firefox OS (and Android and the web at large!) because your apps can be ready for the big launch.

Install the Firefox OS Simulator from today!

Screencast showing Firefox OS Simulator in action

(If you’ve opted in to HTML5 video on YouTube you will get that, otherwise it will fallback to Flash)

Getting help

If you spot any bugs, please file them on GitHub. Got a question? You can ask us on the dev-webapps mailing list or on #openwebapps on

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. Wim

    Is there a way to test the localizations too?

    December 12th, 2012 at 00:53

    1. Robert Nyman

      If you go into Settings, you can change between a few languages: English, French etc. If you want to add your own languages, I believe the best way right now is to download Gaia and test that locally.

      December 12th, 2012 at 04:26

      1. Sheva


        January 31st, 2013 at 22:59

  2. nico

    Let’s try it!
    thanks robert

    December 12th, 2012 at 01:37

    1. Robert Nyman

      Thanks, hope you like it!

      December 12th, 2012 at 04:26

  3. p4bl0

    I had a live demo [1] of Firefox OS by Tristan Nitot a few months ago as Pas Sage En Seine [2] in Paris, and it was one of the selling point that at any time the user can view the html source of whatever Firefox OS is displaying on the screen (see [1] at 55:00 approximately). This is really awesome because it means that you can always study how things work and easily improve them.

    Does anyone know how I can view the html source of what is displayed on screen in the simulator.



    December 12th, 2012 at 03:05

    1. Robert Nyman

      Glad you liked Tristan’s presentation! To my knowledge, right now, you don’t have an option to see that in the Simulator. But I agree, that would be nice!

      December 12th, 2012 at 04:27

      1. p4bl0

        More than nice I think this is an essential feature, since it would be the best possible way for developers to learn how to do things.

        What would be nice would be to be able to edit the html / css / javascript files on the fly on the phone itself to be able to improve or add a feature at anytime (maybe this feature should be opt-in in the settings menu so only people who know what they do enable it). This would feel like Emacs and I would love that.

        I can’t wait to have Firefox OS on my actual phone!

        December 12th, 2012 at 04:40

        1. Robert Nyman

          Yes, there are many ways to try and make it easier/better for developers. First step now, is that anyone can create an app on their local computer and try it directly in the Simulator.

          Next step hopefully contains ways to view the source code for apps etc!

          December 12th, 2012 at 04:47

        2. Kevin Dangoor

          The usefulness of View Source doesn’t extend that far with modern webapps, especially if you imagine it on a small phone screen. That’s why the Firefox Developer Tools are getting more and more remote capabilities. On your full size monitor, you can currently explore the JavaScript code and console logging. Later, you’ll be able to explore the DOM and CSS as well. I think this is much better for seeing how an app works than on-device view source…

          December 12th, 2012 at 06:25

  4. Pravin

    I am trying to run it for last 10 days but it is not working and giving error. something like this,
    unresponsive script: a script on this page may be busy……………………..script: resource://ger/module/xpprovider.jsm:1115

    what should I do?

    December 12th, 2012 at 05:05

    1. Robert Nyman

      Please follow the options under the heading “Getting help” in the article above.

      December 12th, 2012 at 07:08

  5. Mixalis

    It does not work for me. I am getting these messages.
    No protocol specified
    No protocol specified
    Error: cannot open display: :0.0
    info: r2d2b2g: linux/b2g/b2g-bin terminated with 256

    I am using Aurora on Debian Gnu/Linux 6

    December 12th, 2012 at 08:38

    1. Robert Nyman

      Like mentioned above:

      Please follow the options under the heading “Getting help” in the article above.

      December 12th, 2012 at 08:39

  6. Ken Saunders

    Would your input help?

    December 13th, 2012 at 03:17

    1. Robert Nyman

      I’ll ask. I believe that page is mostly as a marketing page/aimed at app developers, but I’ll see what they say.

      December 13th, 2012 at 03:35

  7. LouCypher

    Is there Firefox OS simulator for XULRunner?

    December 14th, 2012 at 14:13

    1. Robert Nyman

      To my knowledge, there isn’t anything similar to that.

      December 17th, 2012 at 03:19

  8. tech forum

    How to install this operating system in my mobile any suggestion or tutorial pls help me if through dual boot then it’s good for my mobile.

    December 17th, 2012 at 07:40

    1. Robert Nyman

      Please take a look at Building and installing Firefox OS. The idea with the simulator, though, is to be able to test it without needing access to a device.

      December 17th, 2012 at 07:53

  9. Sudhanshu Aggarwal


    Its not compatible with my firefox (v14.0.1). Can you tell me which firefox version will be compatible with this addon? I’m running Windows 8.

    December 19th, 2012 at 04:57

    1. Robert Nyman

      Off the top of my head, it should work. First, try updating Firefox to version 17 (the latest). If that doesn’t help, please file an issue.

      December 19th, 2012 at 14:51

      1. Sudhanshu Aggarwal

        Hey! Thanks updating worked! this OS looks smoooooth! ;)

        December 31st, 2012 at 09:59

  10. bikash

    How can I start building my own apps and deploy it to simulator?

    December 26th, 2012 at 12:15

    1. Robert Nyman

      The Getting started guide is probably a good start!

      January 22nd, 2013 at 06:39

  11. Sergey

    looks very fresh, works fast. I love it, want to have this OS on my phone.

    January 22nd, 2013 at 06:13

    1. Sergey

      who knows how to turn on landscape mode?

      January 22nd, 2013 at 06:26

      1. Robert Nyman

        Unfortunately landscape mode isn’t a feature, yet.

        January 22nd, 2013 at 06:40

        1. Sergey

          thanx, then I wait untill I can buy a real Firefox cell-phone)

          January 22nd, 2013 at 06:42

          1. Robert Nyman

            I hope landscape support will be there in the near future, but I can’t promise anything.

            January 22nd, 2013 at 06:46

    2. Robert Nyman

      Sounds good! :-)

      January 22nd, 2013 at 06:39

  12. Michael

    I’m testing the device storage api in the simulator. It works great in general, but I’ve got problems when I pass “sdcard” to “getDeviceStorage”. In this case I get “null” instead of a devicestorage object. I asked in the irc chat and somebody told me to create a subdirectory “fake-sdcard” in the profile folder, which simulates a real sdcard. But it still does not work.

    Have you got a hint how to get this working?

    February 6th, 2013 at 13:14

    1. Michael

      I’ve updated the simulator add-on to the newest version and it’s working now.

      February 9th, 2013 at 00:57

      1. Robert Nyman [Editor]

        Good to hear!

        February 12th, 2013 at 03:29

  13. alex

    i have installed Firefox OS simulator but i can not launch it help

    February 9th, 2013 at 03:00

    1. Robert Nyman [Editor]

      Please file an issue to get help with that!

      February 12th, 2013 at 03:29

  14. Haard

    can i install this os in my Samsung galaxy mini ???? Mr. Robert nyman ??? & if yes then how ???

    February 11th, 2013 at 11:06

    1. Robert Nyman [Editor]

      No, the Simulator can’t be installed on a Samsung Galaxy Mini. For experimental support for the mobile operating system itself, I recommend reading Firefox OS: Devices and Dark Matter

      February 12th, 2013 at 03:21

  15. Harisankar PS

    I am going to update my firefox just to try this out.. :D

    February 12th, 2013 at 02:41

    1. Robert Nyman [Editor]

      Sounds good!

      February 12th, 2013 at 03:20

  16. Nelson Silva

    Really nice simulator add-on.
    Congratulations, Robert.

    February 12th, 2013 at 07:36

    1. Robert Nyman [Editor]

      Thanks! I haven’t built it, but I’m happy Myk did! :-)

      February 12th, 2013 at 07:40

  17. Nelson Silva

    It’s really nice!
    This simulator will have a second version?

    February 12th, 2013 at 08:02

    1. LouCypher

      It already has version 2. Just update your Firefox OS Simulator from Add-ons Manager.

      February 12th, 2013 at 11:21

      1. Nelson Silva

        Thank you. Updated. :)

        February 12th, 2013 at 15:39

  18. Richard Sierakowski

    How accurate is the simulator for the Peak environment? I think we could only ever sell the Peak in the UK as it has a just about reasonable hardware spec.


    February 17th, 2013 at 13:22

    1. Robert Nyman [Editor]

      It’s a simulator for Firefox OS in general, not simulating hardware or performance.

      February 18th, 2013 at 02:56

  19. Spandan Pradhan

    I installed the firefox os simulator add on , but now i am stuck, what to do now. Isn’t there any documentation or tutorial video link.

    February 25th, 2013 at 10:47

    1. Robert Nyman [Editor]

      Not sure what you mean. The screencast in this blog post shows how to work with it.

      February 26th, 2013 at 16:45

  20. lamine

    Thank you for demonstration,

    I have seen tests under Galaxy S2, I found square icons Pretty good,

    is it possible to get this configuration of firefox Os ?


    February 28th, 2013 at 02:20

    1. Robert Nyman [Editor]

      Not right now, but hopefully you’ll be able to customize it through HTML5, CSS, and JavaScript.

      February 28th, 2013 at 12:03

  21. viswaprasath

    how will you get the simulator’s id as we will get in android as getDeviceID().

    March 6th, 2013 at 06:16

    1. Robert Nyman [Editor]

      Not sure. What would you use the id for?

      March 7th, 2013 at 01:17



    I am doing a project using Mobile where i will be using the IMEI number of the mobile as a encryption key. So i tried in my Android simulator i got this method, if I have like this option in the Firefox OS simulator then i can show demo of my project using Firefox OS simulator itself.

    March 7th, 2013 at 03:42

    1. Robert Nyman [Editor]

      Ok, I see. To my knowledge, there is currently no way of finding that out. Try asking in the dev-webapps mailing list.

      March 7th, 2013 at 04:49

Comments are closed for this article.