What do you mean "built-in containers"? AFAIK, there's no way to interact with the built-in containers without an extension to expose it. That was at least true when it launched (e.g. the Facebook container extension was awesome), and I've been using the multi-account containers extension ever since.

Here's how I use it:

• no container - no logins at all
• "personal" - my email and related things
• "work" - work email and related things
• "shopping" - online stores
• "financial" - banking and investments

And so on. Each group has limited access to cookies to scrape. I also have accounts at the same service in different containers and can have them side-by-side.

If this is now built-in, awesome! But I was under the impression that you need some form of extension to access it.

I removed the Facebook account containers extension recently, and it seemed it also removed the multi-account containers extension? I still had containers and could use them however, but I discovered something was up when I could no longer use the ctrl+. shortcut to choose a new container tab.

FWIW I recently stopped using the extension due to large resource usage - especially painful if you have many tabs open and FF opens many processes for each container tab, eating up more RAM. I just use FF Nightly for personal stuff and regular FF for work.

@RmDebArc_5 I love containers, that's one of Firefox's strong points IMHO, I use it *a lot*. My main complaint is that it doesn't handle domains, which is a pain for example with Medium.com, Google.com etc. websites, you have to manually add them all 😓