It is processing tabs, one by one. So when stashing tabs it takes ages.
Firefox allocated 8GB of RAM and crashed (I have few thousands tabs opened).

It is storing "stashes" in a bookmarks which is good.

When tabs are finally stashed, then it is using about 500MB of RAM just to show a list of "stashes".

Tab Stash is amazing. It's really useful for what it does: keeping your bookmarks organized. I’d kindly suggest an improvement—a backup system or export functionality

I'm in love with this extension! Would love to see it on Chrome based browsers too (please port it, I desperately need it lol)

best tabs add-on I have used so far.

非常好用

Be ye forewarned... do not jump right into this or any other open tab manager if you have a lot of currently opened tabs that you expect the extension to help you sort out.
My fault really, but intending to just look around, I hovered & then clicked to stash on a filtered selection. Not seeing a way to pause, cancel or undo; I could only let it run. How bad could it be?
It not only "stashed" the ~500 tabs from the filtered selection, but threw the other 3200 tabs in with. Then to my horror found that it put every single one of the 3700 tabs into "hidden tabs".
I only learned of this after a frantic race to shut down every other process & service on the machine to free up as much of the 32GB as possible, praying that Fx wouldn't crash.
It finally ended, and after wasting a bunch of time trying to find a solution, have now resolved to spending more time cleaning up the resulting mess than it would have taken without the help of the extension.
Badly needs an Undo. Badly needs Select/Unselect All on filtered lists. There's not even the ability to Tap-Space to keep selecting in a list, it's a slog of one-click-at-a-time. Badly needs a setting to only affect what is selected and don't mess with anything else.

I'm sick of this add-on, it lives its own life and constantly refuses to restore the last tabs of the session

I've been a Firefox user since ver. 2 and this is my very first extension review. It's an essential complement to get your bazillion tabs back after an unexpected error or closing the wrong window. Simple and easy to use, thanks Josh!

I hope I could have found this sooner! I got rid of other browsers for this. Now I can have my tabs backed up without worrying to lose them. So I can watch my content whenever I can. Totally worth it!

Good one. I hope for a similar add-on for Chrome...

The best tab organizer on the firefox.

Amazing add-on ! I've found just what I was looking for a long time ! It's a perfect substitute for "Pocket" or "Read it later" add-ons ! And all the tabs are synchronized between devices through bookmarks sync of Firefox !