Nice extension but it may take some time to understand how it works and some sites become extremelly slow because of it, in my case it is Jenkins (configuration pages, plugins page).
Also, it lacks some features:
- save extra fields, like account name/number, etc (e.g. AWS)
- it does not populate login and password on some sites, although it can save them (e.g. Sonatype Nexus)

If you have other passwords to store than those of websites and/or you want to have the storage under your local control, then KeePass is awesome, and out of the different variants KeePassXC is the best one (IMHO). This add-on makes it even better! Thanks!

Shortcuts don't work :(

Pratique, mais pas très intuitif : l'intégration est minimale et il faut repasser par KeePassXC régulièrement.

Gros problème de gestion de l'obsolescence : depuis plusieurs jours, le plugin n'est plus utilisable car il demande la toute dernière version mineure 2.4.* alors que le gestionnaire de paquet de ma distribution (pacman) propose toujours la 2.3.4 et seul une beta de la 2.4 est dispo sur AUR.
Une rétrocompatibilité aurait été bienvenue, même temporaire, afin d'assurer un suivis pour les utilisateurs moyens qui ne vont pas chercher à compiler les source depuis un GIT et se reposent majoritairement sur leur gestionnaire de paquets.

This extension works very well and I love the way it works, couldn't be more happier. The only thing that won't work for me is HTTP Basic Auth. According to documentation, it should work, but I don't know how to do it. When I'm presented with a basic auth form, nothing happens on the extension's side. No way to trigger it, to auto-fill, to summon the extension's dialog to choose a login... And I couldn't find anything in the documentation on how to enable HTTP Basic Auth to work with KeePassXC-Browser.

Added: Thanks! That worked.

Very reliable and configurable.

All works well and tech support for this plugin is very good. I had a problem and they helped me fast.

Spent a lot of my time just trying to get it to work. Finally I've done it but I'm an IT technician and I believe that most of regular people will fail here.
And according to the feedbacks it seems there is a lot of such failed tryouts when people can't even start to use it. Please do something with that.
For example my case was that:
1. Different versions (64-bit FireFox against x86 KeePassXC portable). Extension runs proxy but nothing happens futher - extension doesn't see proxy running or something like that. Fail.
2. KeePassXC (installed) doesn't make org.keepassxc.keepassxc_browser_firefox.json nor apropriate registry entry - proxy doesn't run. I believe that's because of UAC and permissions. Still hothing works. Fail again.
3. Portable x64 KeePassXC + Firefox x64 - win. It creates json and write proper registry key. Extension runs proxy and they both interact each other.

To follow up on (https://addons.mozilla.org/en-US/firefox/addon/keepassxc-browser/reviews/1279287/)
I also feel this extension has little to no use (especially for Firefox) First of all. the auto type sequence is a highly dangerous function. Even if the record inside the keepass database is all set to work for multi page logon, and one changes the global settings by accident. (or update!) all the custom fields are vanished Thus text is just injected into space.
And this is just a KeepassXC bug/~feature~
*sidenote: On Chromium on ubuntu the extension just works out of the box.
On firefox 10 out 10 times this extension is not connected to the database and even if the extension believes to be connected its not, due to KeepassXC not getting kicked alive.

For these hasles it it just not worth the effort.
Just learn the keyboard shortcuts to quickly find and copy the fields needed and insert them manually. The proxy to tunnel the uname/pwd into the browser will not be available i assume.
Second to that: I believe that if your pc is already in a state where you can't trust your computers (basic) functions as per example the clipboard; one has a whole lot of other problems to deal with prior to thinking about security and privacy enhancements
endnote: 5 (Five) stars for the time and effort from the team on KeepassXC itself

Works well for me! Just wished such an addon existed for Opera, too...

The issue that I have is that I don't understand what is the problem that this extension is trying solve. In order for it to work at all, you have to have KeePassXC already open and accessing the database that you are interested in. Other than this, modern browsers already do autofill of names and passwords that you have supplied, the latter being transparently encrypted by the browser itself. I am sure that there are legitimate uses for KeePassXC-browser but, as far as I am concerned, it is far more trouble than it is worth.

UPD: works as intended. Issue that was described here is gone.