Not Free

Regularly breaks. What I mean is that, if you log in and enable the VPN upon first installing it works. Then use firefox as normal, exit firefox, open firefox again etc. and eventually the addon will just hang. You click the little icon to manage it and it just shows a loading wheel. Won't let firefox connect to the internet while it sits there broken. The only fix is to uninstall and reinstall the addon which requires logging in all over again. Very buggy.
Additionally, leaks DNS.

You should let me use the free version first so that I can see if the product is good or not before buying it, but no, you keep popping up notifications to buy, buy, buy, and choose not to let me use the free version. Well, you chose to be the world's worst VPN extension.

Missing refresh token

[WasteOfTime] Proton sounds so legit n rightous, - but if you look close things change fast... whats the use of an VPN if you cant install it!? 8/10 of the installation guides does not work and create a rabbit-hole in the FAQ section, that draws more question than it solves... IT IS INSANE what happens here barely possible to install and use at all.... BUT HEY : YOU JUST HAVE TO UPGRADE TO PbLAN RIGHT - THEN ALL WILL BE GONE ....ah.. 4sure NOT ....LOL Seriously dont waste your time here its insane: "If you make an extension and deny the people the fact that it s not possible in the free edition YOU LIE 2 THEM !!! ...and waste their time through your censouring - framing into an ALL IS GOOD onesidet point of view. How zynical asking for support against censorship! But dont have the guts to indicate negative aspects from the beginning to stay concise!???

Completely unusable for free users. At the very least, I should be allowed to use it to configure options available to a free account and not just be stuck with the regular app to do the same thing.

Free version is non-functional, don't waste your time setting up an account.

VPN doesn't work with Firefox Containers. Split tunnel is only whitelist mode when it should be blacklist instead. Doesn't have the same feature set as the desktop app. Plus Proton is stubborn in not implementing SOCKS5 to make it work with Firefox Containers even though Mullvad does it.

For anyone coming here, just subscribe to Mullvad instead and use the advanced proxy settings for Firefox containers.

I really love Proton as a company but this add-on is infuriatingly buggy. Every time I boot Firefox, it will not reconnect and I have gotten to the point where I have to disable and re-install it to get it to work. I never had this problem with Nord and Proton offering a Firefox extension was a big factor in my decision to switch. I have no idea why it won't connect either because the way it is designed means it just sits there in a window with a spinning pinwheel and won't give me any information about what it's doing.

Waste of time. I chose the free option for FF Linux, but you can not do anything with it, there is no country available, all the options are turned off.

doesn't work on free plan

no app for arm hardware so far as I can tell

works for paid plans only

The proton vpn desktop version is free but this is not.

proton has free vpn service in desktop but this extension won't work if you're not premium plan, LOL

went through all the steps to get it to work, made an account, whatever– and when i opened the extension to turn it on, all the countries are grayed out and the only button available is one telling me to upgrade my plan. i got this extension because it was supposed to be free. clearly, it is not. incredibly disappointed.