Is there a browser (or browser-add-on-combination) which allows to completely isolate each tab from each other/put each one in a separate session? In more detail:

  • not just separate cookies but also separate flash cookies, dom storage, etc., a website in one session should have absolutely no way to communicate (via my browser) with a website in another session even if it's the same website
  • possibility to assign default sessions for new tabs based on URL/Domain (e.g. "no match"→new session, "domain=google.com" →session="google", "domain=youtube.com"→session="google"). If this isn't possible then at least a setting so new tabs get a new blank profile by default
  • persistence on browser restart (tab→session assignment stays intact)
  • per session configurable persistence of session data on browser restart. If not configurable then must be persistent for all of them.
  • possibility to move tabs from their own session to the one of another tab. Optional, could also just paste URL to a new tab in the session where it should go and close the old tab.

I'm aware of questions here with similar answers, concerning multiple logins to the same sites in the same browser. But this is a slightly different question with a different set of answers (which may overlap but aren't identical).

  • Multilogin for Google Chrome seems to save neither session assignment nor session data, not okay.
  • Multifox for Firefox does save session data, but there is no way to open new tabs in new sessions by default and some configuration options are missing.
  • Priv8 for Firefox seems similar to multifox, maybe a little better. Would still need some more configuration options to really answer my question.

What I don't know for both of them is if they actually separate tabs properly, or if they just separate (ordinary, not flash or dom) cookies, which should be enough for most log ins (which is their stated purpose after all) but not for a privacy and security enhancement?

More and better possible solutions would be nice, otherwise I'll need to dive into the code of those two mentioned plugins and figure out what I need to know and add the missing features (which actually sounds like work and I'm lazy, but who knows, maybe I'll do it. If I do I'll be sure to answer my own question here. For Multifox it might be doable with an acceptable amount of work, I think).

Rationale: It's going on my nerves to get tracked all over the internet. A browser with the features I describe would have most of the features needed to foil most of that tracking save for very advanced one. Combine this with spoofing some additional information (screen resolution, os, browser version, plugin versions, etc.) and there is absolutely no way left to track you but for your IP address, which you likely share with quite some other people so it's not usually used for tracking. All this without reducing usability noticeably. The only downside of using a browser profile per domain/tab I can think of is that if you login to a site like a stack exchange using another site like Google, then you need to enter your password again, even though in principle, in the "google.com" browser profile you are already logged in. This could be mitigated by (manually) keeping record of which domains are operated by the same company and thus should go to the same sandbox. By sending and receiving that information to a central store (or P2P, whatever) even this could be reduced to almost nothing.

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    It seems like separate flash cookies would be one of the biggest challenges. Commented May 25, 2015 at 21:42
  • I wonder how incognito/private mode does this. Need to check.
    – Nobody
    Commented May 25, 2015 at 21:57
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    I ran a test for you using ie.microsoft.com/testdrive/Browser/FlashCookies to see how Firefox's Private Mode handles it. Assuming the test is accurate, it appears that Firefox's Private Mode somehow keeps separate flash cookies in the regular mode versus the private mode. Haven't had time yet to determine how they do it. Commented May 26, 2015 at 0:17
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    @Nobody does this work for you? Commented Aug 1, 2015 at 21:34
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    @StéphaneGourichon I added a rationale to my question. By the way I've been using Priv8 for a while, in principle it has the right technique, would just need some more "steering" logic, for when to use new/which sandboxes and configuration options.
    – Nobody
    Commented Apr 6, 2016 at 18:21

5 Answers 5


Firefox 57 AKA "Firefox Quantum" now allows isolating tabs by introducing a "Contextual identities" AKA "Containers" API for extensions. Mozilla has released the Firefox Multi-Account Containers extension which takes advantage of this API.

Containers work by giving users the ability to place barriers on the flow of data across sites by isolating cookies, indexedDB, localStorage, and caches within discrete browsing contexts. For instance, the browser storage associated with a user’s Personal Container is separated from the user’s Work Container. In this way, users can take on different identities depending on the context they are in – we refer to this as contextual identity.

Adding information for each bullet point in the original post:

not just separate cookies but also separate flash cookies, dom storage, etc...

As per the Mozilla wiki "Security/Contextual Identity Project/Containers" article:

Separated by Containers:

  • Cookies
  • localStorage
  • indexedDB
  • HTTP data cache
  • Image Cache
  • Any other areas supported by originAttributes

possibility to assign default sessions for new tabs based on URL/Domain

On this, I'd use the extension, Containerise in addition to Firefox Multi-Account Containers.

Automatically open websites in a dedicated container. Simply add rules to map domain or subdomain to your container.

  • persistence on browser restart (tab→session assignment stays intact)

  • per session configurable persistence of session data on browser restart. If not configurable then must be persistent for all of them.

Firefox Multi-Account Containers allows persistent sessions. For non-persistent sessions, the extension, Temporary Containers should allow opening of new tabs on temporary containers.

Open tabs, websites, and links in automatically managed disposable containers. Containers isolate data websites store (cookies, storage, and more) from each other, enhancing your privacy and security while you browse.

possibility to move tabs from their own session to the one of another tab. Optional, could also just paste URL to a new tab in the session where it should go and close the old tab.

This can be done with Firefox Multi-Account Containers, by right-clicking the tab and choosing reopen in container.


Ghost Browser was designed specifically for the purpose of multilogin. Every time you open a new tab, you can put it into a new Session. (disclaimer: I'm the founder)

The new tab will be a separate color so you can distinguish among them. It looks like this, if you are, for example, logging into multiple Facebook accounts:

multilogin in ghost browser

What's more it's built on Chromium so you can use it like Chrome and auto-import all of your Chrome extensions on installation.

It handles persistence on restart too...actually it goes one better. You can save a set of tabs - with different Sessions - as a Project (Also shown in the image). Every time you open the Project you'll be logged in in the right accounts (unless the cookies have expired of course but checking 'remember me' when you log in minimizes this).

Flash LSOs and local storage are also separate. Cache is not separate yet but it's working in a dev version...coming soon.

If you are in Facebook or Google in the purple tabs, they can't track you in the orange.

With the new Ghost Proxy Control feature you can also assign a different proxy to each color, so that's covered too.

  • Looks like I might be able to accept this answer after having tested it throughly, it's certainly the best answer so far.
    – Nobody
    Commented Apr 23, 2017 at 17:23

Run separate browser profiles for each session you want to have and make appropriate shortcuts.

For Firefox on Windows, edit your shortcut to add:

-no-remote -P

For Firefox on Linux, edit your shortcut to add:

-new-instance -P

To the end of the shortcut. This will run a new instance and let you create a new profile to use for your new session to keep it separate. Don't run multiple instances in the same profile.

For Chrome, you can either go to settings and make a new user to switch between, or make a copy of your Chrome shortcut for each session you want and a separate directory for your profile. For each new shortcut, edit it to add:


And the path to the profile directory you created for that profile. For more you can use randomized folder names by using openssl rand:

--user-data-dir=`openssl rand -base64 4`
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    There is a large gap between what OP asked and you answered. Two isolated profiles are completely different from two isolated tabs. The goal is to have two tabs opened isolated from each other as if running two different profiles yet remaining in one window. Multi-profile creates multi-windows as well, and you can't make them come under one roof. If you know you can then please edit. Otherwise, it's better to mark that you proposed an alternative here.
    – Firelord
    Commented Jun 3, 2015 at 9:23
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    It's the only way to get the separation asked for. I don't think you could combine them into the same window without some 3rd-party software. Extensions can get close to this separation, but the separate sessions asked for is best, and that's what I answered here.
    – Tanath
    Commented Jun 3, 2015 at 19:55
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    I won't delve into any discussion now (reserved for Meta only) but there exists a fine line between what you don't think and what's possible or not. You've not backed up your claim for why two isolated tabs isn't possible (btw OP is ready for 3rd party software). Since you've not done so, ultimately, what you proposed appears to be an alternative to me. Not that I've any issue with it because it is still a useful answer, however, it is an alternative and a note should be mentioned for the same. Anyhow, the community will decide it by +1/-1. :)
    – Firelord
    Commented Jun 3, 2015 at 20:03
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    They asked how to separate them and/or have different sessions. I showed how to do that. It solves their issues except for using a single window. Only in that respect is it an "alternative". I don't believe there is currently a way, but I can't rule it out.
    – Tanath
    Commented Jun 4, 2015 at 0:49
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    To more easily distinguish between the different profiles, try installing a separate skin/theme on each profile.
    – Flimm
    Commented Apr 2, 2016 at 11:17

There is plugin for Chrome called SessionBox and works like a charm.

Local sessions are unlimited, but when you are interested in synchronization sessions between multiple devices, you are in free version limited to 1 session. For unlimited synced sessions there is a fee of 1$ per months, which is not bad. :-)


You should have a look at Tails, which is used by reporters in "difficult" countries: https://tails.boum.org/

Physically removing your hard drive and running Tails from a CD or DVD, makes your system "read only" : your browser cannot write cookies to the hard drive and your next navigation session will be independant, as long as you switch off your router enough time, so that your Internet Service Provider (ISP) will assign it a new IP adress when you start it again.

However, I'm not sure how such system handle cookies ; if they are simply ignored, or if they are written to into RAM.

Another concern is who is behind the nodes of Tor. Not necessarily angels.

Lastly, your ISP has the final word about your privacy.

So, Tails is certainly an improvement for your privacy when run from a DVD, but don't ask it more that what it can do.

  • This is unsuitable for my problem. But actually no, with TOR, your ISP can only cut off your connection, they can't listen in. Plus it makes you a target, using Tor makes you stand out. Plus the browser in Tails is a pretty standard Firefox I think (maybe permanently in Private Browsing mode, which is mainly good for browsing privates and not so much for security). Plus the browser does store cookies, regarding permanent browser storage this is like setting up a new profile after each reboot (i.e. during your session, it doesn't provide help isolating tabs).
    – Nobody
    Commented Apr 23, 2017 at 17:20

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