While Mozilla is still hard at work to integrate the multi-process architecture e10s in Firefox which is a prerequisite for sandboxing in the browser, add-on developers are already one step ahead of the organization.
The new Firefox add-on Priv8 adds sandboxed tabs to the web browser using the security model of Firefox OS. It enables you to run select tabs in a sandbox which separates it and its data from the rest of the browser and other tabs. Please note that it has been released as a proof of concept right now.
The system works by creating sandboxes and assigning domains to it. While that is less comfortable than a sandbox that works automatically, it does introduce interesting features to the browser.
The first thing you need to do after installation of the Priv8 add-on is to create one or several sandboxes. This is done with a click on the extension's icon in the browser's main toolbar and the selection of manager from it.
Click on create new sandbox, add a name and select a color for it. Once the sandbox has been created, add a url to it on the main page that you want to associate with it.
One interesting option here is to create multiple sandboxes that use the same url. Since sandboxes don't share data such as cookies, it can be used to access as many accounts as you want on the same website without any issues that goes along with that usually.
If you have two Gmail accounts, you can sign in to both and use them at the same time. You can also use a sandbox for Google Search or YouTube and stay signed out when you use them.
You need to open the sandbox with a click on the open button next to it. If you open the url manually in Firefox or with a click on bookmarks, you will notice that it is not sandboxed.
It is however possible to use the toolbar icon of Priv8 to open a sandboxed address using it as all are listed in the menu automatically there.
Sandboxes and the data that gets saved to them, cookies, storage and cache files for example, persist over sessions. This means that you stay logged in if you are signed in to an account for example.
You can distinguish sandboxes by their color. It becomes visible on the active tab and when you hover the mouse cursor over any inactive tab that is sandboxed.
Priv8 is an interesting add-on, one that highlights how powerful Firefox's APIs for add-on developers really are. It is too early to tell how well the add-on protects or secures the browser and its data, but the separation itself works fine which you can test yourself by simply running the same domain in two sandboxes.
This is definitely one of those add-ons that you should keep an eye on. Well done.