I recommend this session manager rather than the one that Mozilla recommends.
Session Boss saves sessions automatically when changes happen, not in a fix time schedule. No unnecessary backups and nothing gets lost.
You can decide whether to keep or remove the current tabs right when restoring a session. It is not bound to a fix setting.
I am very contented with this session manager.

TL;DR The extension current state as of 11-Jul-24 is slow, functionally insufficient, visually unappealing, & Unreliable.

Session Boss is a poorly executed session manager that hinders user experience due to performance bottlenecks, feature deficiencies, and an outdated design & interface. infact it's a prime e.g. why people flee to better tab managing browsers ecosystems (chromium native support for tab management is not great but the extension support to manipulate the behavior makes up for it)

The extension's performance issues are particularly egregious when dealing with large numbers of tabs. A session with 1,500 tabs took over 30 agonizing minutes to restore using Session Boss. In contrast, Firefox's native solution (about:sessionrestore) accomplished the same feat in mere seconds. takes a minute or 2 to completely do its job of restoring the tabs with their associated groups in the tree style tab with no laggy experience at all. Otherwise it does what it suppose to do. backs up your tabs & its structure by both on schedule & change basis but in order to do that it consumes too much CPU making your browsing miserable. i.e. not optimized for a session manager.

Furthermore, the extension's performance woes extend beyond session restoration. General browsing becomes sluggish, and video playback is plagued by stuttering and lag. & worse it makes tree style tab slow & laggy. which makes it even more frustrating.


Session Boss boasts a feature set that can only be described as rudimentary. It's as if the developer took a core concept and then deliberately stripped it down to its bare bones.
- Basic Operations: The extension lacks fundamental capabilities like selecting multiple tabs for moving, copying, cutting, pasting tabs between sessions, and merging or splitting sessions. These are essential functions for any modern session manager.

-- Duplicate Tabs: Identifying and managing duplicate tabs is a nightmare. There's no built-in mechanism to distinguish between identical tabs, let alone group or remove them.

-- Import/Export: A critical omission is the absence of robust import/export options. The extension cannot import session data from popular alternatives like Chrome's TabXpert or Firefox's Tab Session Manager, nor can it utilize Firefox's native backup files (.jsonlz4, .baklz4). also, Non-existent CSV support. This limitation hampers user experience and restricts data transfer capabilities. & also significantly reduces the extension's utility.

- Organization: Session Boss offers no tools for organizing tabs within a session. There's no option to sort tabs by domain, URL, title, or most recently used. After searching for tabs, there is no way to select and manage multiple tabs across different sessions. This makes managing large numbers of tabs an exercise in frustration.


Coming down to the user interface of Session Boss is outdated and visually unappealing as already said above. It clashes with Firefox's modern design language, creating a jarring and unprofessional look. The extension's slow response times (specifically when deleting the sessions) exacerbate the overall poor user experience. I suggest the Dev. to take a look at partizion.io & tabXpert both of them are great session manager & tab manager in every way. Performance wise, UI/UX wise, Feature Wise, Support wise. plz give them a look.

Data Loss: The extension exhibited alarming instability during testing. In one instance, all saved sessions were mysteriously deleted after a system crash. This is an unacceptable level of unreliability for a session manager. Session Boss's on-change basis and scheduled saving functions conflict, causing delays and additional issues. Re-enabling the extension after disabling it resulted in losing all session data & making the extension unresponsive.


As it stands, this extension is in its infancy and requires extensive work before it can be considered a viable session manager for daily use.

It does fine in remembering the tabs and windows I saved but when i backup a session and try to reopen it it only opens 10-50% of the tabs i had open, and i have to do the rest manually.

Better than session buddy, the best session manager
Edit: LIMITED SESSION SAVES - 2 THUMBS DOWN

Used to work fine until it randomly decided to wipe all my tabs. Nothing could be recovered. Stay away!

Amazing. Best alternative to Session Buddy in Firefox. Supports Tree Style Tabs also. Perfect! I wish it could also restore favicons.

Wish it had a dark mode

Very good, saved me several times. It should be kept up-to-date. Automatic Scheduled Exports would be nice...

Used to work ok but today ALL my saved user sessions simply vanished. With no apparent means to recover them. Thousands of tabs lost.

Has option to open full page view as default. But no closing tabs nor windows is possible.

Everything (GUI, etc) is nice. Except that it seems like it's unable to sync across computer, right?

Intially had the the problem off rare moments where all User sessions would get deleted from a crash or update. Incredible plugin though, i love it. Just make sure you get into the habit of always exporting (backing up) all your user sessions few times a week. Nevetheless, perfect plugin.

its really great if i can merge session, remove duplicate and many operation to clearing up and summarizing my session.... and i cant make storing size more than 99 sessioan?

Excellent purpose.
Phenomenal UI/UX!
Unfortunately it has not been updated since Jun 7, 2019 (V. 2.11.2).

Effusive congratulations to the developer.

It's good, IMHO the best session manager for Firefox, but the problem is, it just lost all the saved sessions for no apparent reason -- and no, I don't have other profiles, I just checked.
To be fair, most (all?) other session managers seem to do that from time to time, at least judging by user reviews. Perhaps it's more of a Firefox thing than this extension's fault, I don't really know. So it's four stars on trust because I don't know who's to blame.

I wonder how does one make automated backups outside of Firefox to work around this issue. Is it enough to copy the files under browser-extension-data/sessionboss@william.wong? Can they be safely copied while the extension is running, or is that looking for trouble? Or can the export be automated somehow?

Besides this, there's a minor UI annoyance: the buttons icons, which look right in the screenshots, for some reason look horrible here, as if they are being badly resized.

This is an excellent add-on but it took me some time how to work it out. Not the most intuitive of apps. But has saved the day a few times now. Best of the session restorers i have tried.

It is somewhat slow in my device, but I just have 4 gb. I love this extension, I'm always use it to order all of my different kind of works.

After closing Firefox I found a pop-up window from Microsoft was still open. Closing that saved it as my last session so I lost all my pinned tabs. Thanks to Session Boss, I was able to export the current session on my other PC then import it to this one. Everything has been recovered including favicons. Brilliant!

The only downside was that Firefox identified a couple of tabs as having errors and would not allow them to be restored.

I use this mainly before closing Firefox before rebooting my computer. The user session save works really well. I live how it saves the container tab being used. Great work - thank you!

Was working OK for the most part. Sometimes would randomly lose sessions. But now it seems dead. Clicking the icon brings up an empty menu frame. And FF addons page says it needs containered tabs and asks to delete it, with no info on what containered tabs are or how to activate it....

I'm really pleased with this add-on! One big issue I noticed today, possibly related to the other review below me (luckily I exported a backup yesterday)... all of my user-saved sessions simply disappeared!

^^ I'm quite sure it happened right after I added a new container name to Mozilla's Multi-Account Containers.

Don't trust this app!

It used to work fine - until today: woke up with my computer having crashed and suddenly NO session was shown in Session Boss to be recovered anymore. Not one from last night, not even a single one from the months and weeks before. I had about 150 tabs open for work and they are now ALL lost!!!!

PS: I cannot even save a new session anymore now, something seems to be completely broken with this plugin... (v 2.11.2)