Getting KeepassXC Working with Snap Firefox on Ubuntu 22.04 LTS

Yesterday, I posted documentation detailing how to move Firefox back to using a native package rather than a Snap.

My motivation for needing to do this was that the move to snap had broken communication with my password manager (KeepassXC) and I needed it back up and running in a hurry.

Things broke as a result of a lack of support for NativeMessaging in snap, so any extension relying on this mechanism will have issues.

This, amongst other things, is something I previously experienced when Chromium was moved to snap a couple of years ago:

Chromium going snap broke a lot

Yesterday, I needed to get things up and running quickly, so looked at how to de-snap my Firefox install.

However, if NativeMessaging support is your only concern with snap, the good news is that help is coming.

There's an updated xdg-desktop-portal which adds support for NativeMessaging, and the beta version of the Firefox snap adds support for communication with local extensions via xdg-desktop-portal.

In this post, I'll run through the process of enabling this communication.

If you've already replaced Firefox with a .deb you can still follow these steps to test the snap support without overly impacting your current install.

Check Dependencies

First, you need to ensure that you've got the right version of xdg-desktop-portal:

dpkg-query -l | grep "xdg-desktop-portal"

The version you're looking for is 1.14.4-1ubuntu2~22.04.1 (or higher, if you're reading this in the future).

If you're sporting an older version, trigger an update

sudo apt-get update
sudo apt-get install xdg-desktop-portal

Install Firefox beta snap

Verify whether you already have a Firefox snap installed

snap list | grep "firefox"

If the firefox snap is already installed (i.e. if there was output above) then switch it over to the beta branch

sudo snap refresh firefox --beta

Otherwise, install a new snap

sudo snap install firefox --beta

Once that completes

Kill xdg-desktop-portal to ensure the new version is used

systemctl --user restart xdg-desktop-portal

Launch the snap based firefox

snap run firefox

You should get a prompt asking whether to allow Firefox to launch webextensions:

Allow Firefox to start WebExtension backend?

Click OK to approve it.

Adjusting Permissions

The snap should come up with your profile in place, so go to your extension and check whether it can communicate with your password manager/whatever.

In the case of KeepassXC you'll probably get

Key exchange was not successful

This is because the permissions aren't quite right in the container by default.

Run the following

sudo apt-get install flatpak
flatpak permission-set webextensions org.keepassxc.keepassxc_browser snap.firefox yes

Then re-launch Firefox.

It should now work, and Keepassxc will prompt you to provide an identifier for the browser.

Name this browser

Extension Conflict

If you're still not prompted, it may be that other extensions are interfering.

To check for this, exit firefox and then run

MOZ_LOG=NativeMessagingPortal:5 snap run firefox

Look for lines referring to KeepassXC to see whether communication is successfully being established (linebreaks added for clarity)

[Parent 45315: Main Thread]: D/NativeMessagingPortal got file descriptors for native application
in session /org/freedesktop/portal/desktop/session/1_301/firefox_org_keepassxc_keepassxc_browser_1791972916:
(167, 168, 169)

If that's there, look for reported failures for other extensions - on one system I found that 1Password was having issues

[Parent 45315: Main Thread]: D/NativeMessagingPortal session 
/org/freedesktop/portal/desktop/session/1_301/firefox_com_1password_1password_3847301527 was closed 
by the portal

[Parent 45315: Main Thread]: D/NativeMessagingPortal cannot close session 
/org/freedesktop/portal/desktop/session/1_301/firefox_com_1password_1password_3847301527, unknown handle

It appears that these failures can impact the initial communication between the browser and KeepassXC.

To get KeepassXC connected

  • go into the browser and temporarily disable the affected/failing extensions.
  • Restart Firefox
  • Attempt to connect to KeepassXC: you should now get the prompt to name the browser.

You can then re-enable the other extensions, and should find KeepassXC continues to work even after you've restarted Firefox.

Adding permissions for other extensions

If you've other extensions which aren't working, start by checking permissions:

flatpak permissions webextensions

Table         Object                           App          Permissions Data
webextensions org.keepassxc.keepassxc_browser  snap.firefox yes         0x00

You're looking for a yes in the permissions column.

If your extension doesn't appear (or is set to no) you can discern the object name from the loglines you looked at above.

For example

session /org/freedesktop/portal/desktop/session/1_301/firefox_com_1password_1password_3847301527

We ignore everything up to and including firefox_, giving


The number at the end is a session identifier, so strip that and convert underscores (_) to periods (.)


We can then set permissions with flatpak

flatpak permission-set webextensions com.1password.1password snap.firefox yes

And the extension should then be able to communicate with 1password's local agent (if it's available).


It's still frustrating that Firefox was moved to a snap despite knowing it breaks something so fundamental as extensions. It really shouldn't be necessary to run beta releases in order to have a new LTS not break existing functionality.

But, fixes are in the pipleline.

Although clearly there are still some teething issues, they'll all fall by the wayside when the functionality crosses over from the beta snap to stable, (though there's some delay).

Application containerisation technologies like snap offer process isolation, which in the long run, should lead to a more secure install, which is undoubtedly a good thing. I still have some reservations about whether something as extensible as a browser will ever be a good fit, but clearly there is at least an appetite to resolve issues.