This extension right here is the smoking gun that convinced me to switch over to firefox, it's insanely useful and a great quality of life tool to manage multiple accounts and no other browser has this. I can now open (for example) YouTube with 2 different accounts or in a new container without an account. They can't track between each other, so it is of course a gigantic win for privacy too.

FOSS: ~./FuckingOssomSshit

Excellent and unique feature of Firefox. Essential

Works great for me, easy to set up.

Honestly the best add-on in Firefox! It's the main reason why I use Firefox on PC. What makes it so unique and amazing is that I can for example have google search in a separate container without signing so I can search privately while having YouTube and Keep and other google sites signed in with my own account or any account I want, no other browser does this, all other browsers force every google site to be signed in with the same google account which makes it if you wanna use YouTube you have to be signed in to google search too which is terrible for privacy. And I can have any site I want open in a separate container which eliminates cross-site tracking completely, a more guaranteed way than using Enhanced Tracking Protection and uBlock Origin which are also fantastic and important to have enabled for privacy as well. This is an absolutely brilliant add-on. THANK YOU MOZILLA!!

There is currently a bug with the popup, where you have to click "Done" every time, which should be fixed soon (see issue 2813 on the mozilla/multi-account-containers GitHub repository).

This extension has always been helpful so I won't rank it down just for one mistake :)

Great extension! The only issue I’ve encountered is with syncing — it seems to have a bug. I never choose “Always remember to open this site with,” yet it keeps automatically assigning websites. Once I disabled Sync, the issue disappeared. I wish there were an option to turn off this feature entirely. Aside from that, it works perfectly!

Amazing must have tool has completely fix dealing with multiple accounts on services.

As others have noted though if the Rate this extension pop-up doesn't go away soon, the stars are going to start dropping.

Excellent!