Awesome add-on!
You can set an URL to use a specific container, I love the safety and privacy this add-on brings!
I wish I knew this before, a friend of mine told me about it.

Estupendo!, usando esta extensión puedo tener varias cuentas en una misma pagina abiertas al mismo tiempo!

Excellent feature. But where did this icon set come from? I understand fingerprint, briefcase, $, shopping cart, and glasses (probably something along the lines of personal, work, banking, shopping, incognito). Some how apples and school has gotten symlinked by our culture. And fence kind of works for private/secure tho its a little bit of a thinker. But airplane. gift, fork/knife, dog, 2 trees, and blob? What kind of obscure use case would make those icons fit? Give us:
magnifying glass (re/search)
newspaper/bookmark (news/reading)
GPS signal (local/geograpically identifiable)
Crowd of people (social media)
Heart (of course for favorites. Or porn. Or favorite porn.)

I feel an essential feature i believe this extension needs is the option to allow saving closed tabs exactly in the way they were closed, the same way multiple Firefox profiles generally allow you to, i don't think it should be a compulsory part of the user experience but it would be nice to have that option, since you could remove a tab and store them basically in this limbo state until you need them again, thereby not re logging every time . All in all an excellent extension i definitely think this is a move in a positive direction and do encourage others to try it out. The add-ons helps you isolate your online profile and it definitely lives up to what it pitches.

Fantastic extension. Greatly superior to needing separate browser instances logged into each different account. 100% recommend this.

Best Idea for browsers

This is an addon that should, IMO, be a feature built into every modern browser.

My only issue with it is that I have never been able to get it to sync properly across devices. Even so, it is invaluable. Just this extension alone is worth a donation to Mozilla.

Very useful for maintaining multiple profiles/accounts on websites.

It's really a nice extension that I was looking from long time
There is an issue when firefox closed by system ( Windows ) It did keep the current tabs but removes the tag ( container ) from it - to be like normal tab without container
It would be nice if we could send the link or page to specific container without opening it or opining all tabs of that container
Thanks

As soon as the extension is deactivated, almost all data is erased! There is no way to recover anything and you cannot make a backup! This makes it INUSABLE. This is a very serious problem that has never been solved!!! Why don't you use Firefox Sync?