Firefox has multi-account containers that allow you to use the same website with several accounts, without having to use a different browser:
Problem: I always open tabs with CTRL-t because clicking takes too much time.
Question: How to open a new work-related tab with the fastest possible keyboard operation?
As of version 7 of the Containers extension, ctrl+shift+1-9 works without any further add-on. From the release notes:
Set shortcuts in the add-on preferences panel:
Ctrl + Shift + {Num}
Which containers correspond to which number can be configured in the add-on preferences.
As mentioned in other answers, ctrl+., tab also works.
On MacOS it's cmd+shift+{num}
According to the Multi-Account Container plugin page, you can use Ctrl + . to open the panel. Then simply press the down arrow (or tab) and enter.
Ctrl + . (period)keyboard shortcut is available to open the containers panel. You can then use tab and the enter keys to open new container tabs.
After Ctrl + . you can also use the numeric keys in order to select a container from the list. (Thanks cyberalex)
It doesn't seem to support opening a specific container with a designated shortcut.
I use https://addons.mozilla.org/en-US/firefox/addon/easy-container-shortcuts/
AFAIK, there are no firefox built-in shortcuts
expanding from @tone7 answer you could Ctrl + . (period) then use number to open corresponding tab
Ctrl + . + [1-9]
I couldn't find a way to do this natively with Firefox, but this extension seems to be doing what you are asking about: https://addons.mozilla.org/en-US/firefox/addon/easy-container-shortcuts/
According to the description:
Provides nine easy keyboard shortcuts to open new tabs on different containers: Ctrl+Shift+[1-9] / or Alt+Shift+[1-9] on OSx. You can also open a new tab on the current container by pressing Ctrl (Cmd) + Alt + T
