In Firefox, I often use several accounts of the same webapp in parallel.

For instance a Twitter account for each of my projects, and several Gmail accounts for various purposes I don't want to mix.

Right now I use different browsers, and setting up each browser to my tastes takes a considerable time. I also tried running Firefox from different UNIX user accounts, but that's quite a pain to run.

Is there an add-on (or browser, or anything) that would allow me to do all of this in the same Firefox window?

I am also open to switching to a different browser, as long as it is an open source browser.
If the solution is an add-on, I prefer the add-on to be open source and if not at least free.

  • For Gmail you can log into multiple accounts at once and switch at will - and use different accounts in different tabs. But that is a built in Gmail thing not due to the browser. Commented Mar 12, 2014 at 8:07
  • I think there will hardly be a browser to support your needs. The problem is that your authentication data is associated with a user session, which is created per client (per browser) on the serverside of the corresponding application (Twitter, Gmail, Facebook and etc.) Some applications like Gmail support multiple accounts per browser session, because of their specific implementation. The latter is not a standard and one should not expect other services (like Twitter) to support it. The closest thing I have used is multiple browsers - one per account, or browsers started by different users. Commented Mar 12, 2014 at 8:15
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    As for starting Firefox by different OS user, it might become a good and easy thing to do if you automate the tedious scripts. I'd create shell script file per user and use it as a launcher for the browser. So I'd have project1.sh to launch firefox for project1 user with its own set of tabs, project2 and etc. Combied with the pin-tabs capability of firefox, this would be a good way to solve your issues. So - try and go with scripts. I hope it works for you. Commented Mar 12, 2014 at 8:19
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    Instead of starting Firefox using multiple OS users, have you considered using it with multiple profiles? Using the ProfileSwitcher addon (I've not yet tested this, or I'd made it an answer), this might even be a much easier approach.
    – Izzy
    Commented Mar 12, 2014 at 12:00
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    Multifox (which is a Firefox add-on) allows this per window, but its beta, AllAccounts, seems to allow this per tab.
    – unor
    Commented Mar 13, 2014 at 17:54

1 Answer 1


Multifox is a Firefox add-on that

allows Firefox to connect to websites using different user names. Simultaneously!

Those identities are called Identity Profiles, which can be named (e.g., "Private", "Work", and "Sockpuppet"). Cookies are shared only within a given Identity Profile (so if you have several windows open with the same Identity Profile, then you have the same cookies on these tabs).

You can switch identities from the toolbar:

Multifox screenshot: toolbar menu for switching identities

So this solution is similar to having different Firefox profiles (which also could be opened from within Firefox, e.g. with the ProfileSwitcher add-on). The primary difference is, of course, that with Multifox you are using the same Firefox, i.e., you have the same settings, the same add-ons, etc., while each profile would give you a new Firefox.

There is also a sibling project AllAccounts, but it less ready for public:

(You should not use both add-ons at the same time.)

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