Excellent.

Drawback: the add-on seems to have been abandoned 4 years ago, as seen on Github:
https://github.com/Peuj/duplicate-tabs-closer

But I find a bug:
Whatever your choice in "Priority" parameter in the Options, the add-on always keeps the oldest visited tab. This parameter seems to not work at all.

And I also have two little requests:
- First one: it would be nice not to include the tabs "New tab" in the list.
- And second one: it would be nice to disregard (ignore) a final "/".

Both requests could have their checkbox in the Option page (with On by default).

But I don't know what to think, given that the developments seem to have been abandoned 4 years ago.

Write about my experience with this add-on? I wasted hours trying to figure out why I could have only one tab per domain. It didn't matter if the url was completely different. Utter POS because the PEUJ who designed it doesn't even know the meaning of "duplicate". IT MEANS "EXACTLY THE SAME", got that? Read again.

big productivity QoL for disorganized compulsive browsers (user)

Seems to work fine BUT ONLY IN ONE WINDOW ... I uses several windows and there are "no duplicates" found by this (and other) tab deduplication extension ...

Because of some somehow gone/lossed tabs I opened a saved session so I had to get rid of duplicated tabs.

Najlepszy! Szkoda, że brak języka polskiego.

Works well - the option to delete newer duplicate tabs goes a long way to not losing anything you're looking at or working on.
Would be cool if there could be a colour, or some kind of alert or badge on the actual dupliacte tab itself.
A one-click, auto-appearing 'close' button would be good too, instead of having to dive into the menu.

I find the 'close all' button and section a bit unclear - both the duplicate and the original tabs are listed, with a cross by each. Does the cross close the tab, or remove it from the menu? Does the 'close all' button close all the listed tabs, or just the duplicates? It's a bit nerve-wracking at first, but once you get used to how it works it's helpful in pruning down serious browsing sessions.

Excellent add on! Can we please get an option to exclude duplicates when a duplicate tab is manually opened?

ne fonctionne pas

It keeps closing som4 local tabs on my network, basic local IPs. Nope.

I tried a duplicate tabs extension that was way simpler than this that I liked at first. It could close duplicate tabs automatically in the background without interruptions, but it stopped working at some point. I tried this one next and it seems to be very robust. I wasn't sure that I needed all the bells and whistles at first but they have turned out to be quite useful after all, such as the URL format filters and the whitelist.

If I could add a suggestion, it would be super helpful to be able to whitelist a new tab. Not sure if this is possible. I tried entering a pair of empty double quotes into the whitelist field "" to see if that would work since I noticed that wildcards are also supported. Kind of a hackerly solution but I took a swing at it. Still closes them though. 😛

Recently the about:blank whitelist fails.

So, this appears to promise automatic and manual resolution - perfect! Reality? You have to fight against this as soon as you don't do what it wants.

The most hilarious part is the manual deduplication. As the other person below notes, the "close all" button really closes all - it does NOT deduplicate your open tabs. That is to say, for 4 duplicated tabs, you get 0, not 1. So, not deduplication. It really is "close all", not "resolve all". In most cases you don't want to press it, ever.

If you want to resolve manually... Well, you get only a tiny bit of space for the list of all duplicates. You have to unpin the settings and collapse, exactly what you thought. Oh, did you think opening the settings in a tab will help, because it will scroll unlike the tiny popup, so you'd get a long list? Nope! Well, then, you finally collapse the settings, clicking left and right. And finally you can see it well - a list of tab names with [x], you click the [x], and... nothing happens! That's right, you have to refresh the whole settings tab to see the list updated. And did you think the list will be the same? Nooo, it is sorted, so as soon as you close one dupe and refresh, the list is in completely different order.

So, what did I expect? Lots more space for the duplicate list. Also, updating it in real time as you close the tabs, so I could just click over on the first item and as it closes, more shuffle back into the position, and of course when the last one remains, it is not a dupe anymore so it goes off the list. I also expected the close all button to do that dance for me.

As to the automatic resolution, that is also a bit weird. When you open all links in new tabs, then it probably works. But if you click a link to open in the current tab and it suddenly disappears, that's not exactly what I expected.

I'm really disappointed. But it does not even look like there are other addons that could do the job instead.