Temporary Containers is a WebExtensions add-on for the Firefox web browser that you may use to open sites automatically or manually in containers that get removed when the last open tab of the container gets closed.
Containers is a relatively new feature of the Firefox web browser. Mozilla revealed the feature -- then called Contextual Identities -- in late 2015 and added it to Firefox Nightly in mid-2016 under the new name Container Tab.
Mozilla launched a Test Pilot experiment in March 2017 to find out whether the feature garnered enough interest to warrant further development.
A container separates content in the web browser. The feature is not as powerful as using different browsing profiles, but it serves specific purposes and is easier to use. Containers keep cookies, local storage and cached files separate from other containers and non-container tabs. Users retain access to bookmarks, passwords or the browsing history, however.
You may use Containers for several purposes such as signing in to the same web service with multiple accounts or separating different tasks in containers to avoid ad retargeting for instance.
Temporary Containers supports an automatic and a manual mode. Links and URLs are opened in containers automatically by default. A new temporary container is created when you open a new Tab Page in Firefox, activate links so that they open in new tabs or browser windows, or activate links from third-party programs.
The main idea of the extension is to open sites in containers to separate data from the rest of the browser. It works similarly to the Firefox add-on Private Tab in this regard which added functionality to Firefox to open new sites in a private browsing tab in the same browser window. Private Tab is not compatible with Firefox 57 or newer.
The temp container is removed when you close the last tab and with it go cookies, cache and other data.
The extension comes with a solid set of preferences that let you customize its behavior. You may disable automatic mode there, and also change the container color, prefix, icon, and number. Icon and color can be randomized as well.
You can disable the automatic nature of the extension to load sites in temporary containers only on manual action. You may set global mouse actions for that, middle-mouse and Ctrl-key (CMD on Mac) and left mouse button, or for specific websites.
Temporary Containers adds other means of opening tabs in containers to the browser. It adds the option to the right-click context menu of links, mapped the keyboard shortcut Alt-C to the functionality, and adds an icon to Firefox's toolbar which opens a new container tab when you click on it.
The extension is open source; you find the source code on GitHub.
Temporary Containers worked well during tests. It has several use cases, for example, to always load links on specific sites in a temporary container or for quickly reading articles without having the site set cookies or add files to the browser cache. It may not offer all functionality of Private Tabs, but if you are mostly concerned about cookies or local storage, it may be an option to deal with that.
Now You: Do you use Containers in Firefox?
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