Brilliant. I had 109 tabs open and I could not find a fast and easy way to move them to my new PC ... until I found this extension. Simple-as extension, pure gold in my case. Go, install it to see what it can do for you.
It looks scary at first as it closes all tabs and presents you with 1 page full with the URLs but you can easily restore. Or in my case export which is in txt format, then I wrote a draft email, opened the draft on my new PC, copy&paste into OneTab's import window, done. OneHappyDude :)

Is this open source? If yes whats the link?

This addon is very useful, but could there be option to not automatically focus to OneTab tab once browser is just started?

Why does Mozilla insist on keeping its pages as bright as the sun?
Please don't follow in their footsteps. This is a great extension but the white background is killing me here.

I'll (without hesitation) give this extension a 5-star rating since it makes the Firefox UX that much better, but give us some sort of dark background!

Please include a dark mode and search function.

A very nice and useful addon, but that white kills the eyes. Please add a simple color chooser for both foreground and background, please.

I love this extension. Sometimes I will have 30 tabs open when researching or working on a project. I don't want to close them because I want to come back to them later. This extension takes them and saves them for you so you can return to them all in one click. It is truly my favorite extension!!!!! I would give it 100 stars if I could!!!

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Information about container is not stored. Tabs aren't restored in container tab like work/media/shopping/…
Missing search/filter input box.

This is one of my favorite extensions. Well designed, works flawlessly, great user interface. You can clean up all of your tabs to a section in onetab (or just add a single tab). The tab will present as lists, which you can name, move things between, delete, etc. Whenever you want to see that tab group again, you can load the tabs as a group (as well as individually). Wouldn't know what to do without it. Great job! Thank you!

Love OneTab, using it on both Chrome and Firefox. Isn't it about time we get a nightmode? There are a couple of extensions that would provide this but non of them work now due to Mozilla cracking down security. Please please please, a night mode.