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

very good

Works fine, don't have any complains as others do here (no DNS leak, no connection issues and also works with Firefox Containers for me)

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.

It's buggy. At the beginning it would keep reconnecting and switching server all the time, though this was a few months ago so I don't know if that's fixed. But now I tried using it again and its supposed to reconnect when restarting browser but instead it gets stuck and doesn't connect. I had to disable the extension. Also if my internet goes out the vpn doesn't automatically reconnect I have to manually disconnect and connect again.

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.

Good server with good speed. The add-on is not bad, but there are sometimes connection drops. The biggest disappointment is that every time me open the browser, the add-on does not create a connection automatically. Each time I have to log in to my proton account and only then manually create a connection. For comparison, the same Proton extension works flawlessly in the Google Chrome browser.

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 nice if you have a paid subscription. Though, would be wonderful to implement reverse version of the split-tunneling, when only sites specified are routed through the VPN.

E.g. if I'm ok with revealing my ip to most of the sites I visit, or I already route all the home network traffic through a local Proton server, but I want to completely hide my location from selected few sites. For them I'd like Firefox to automatically route the connection through a secure-core network. Currently it is only available when you manually connect and disconnect the extension as needed, and I often forget to do so.

Otherwise, a very useful extension

works for paid plans only

Incredibly flaky VPN connection. I can be happiliy browsing then things .... just ... stop. Then I look at the extension icon and it's a warning yellow. It's disconnected with no notification. So I click to reconnect and a notification shows "Connected", BUT the actual window still shows connecting, and more often than not that connection actually fails.

It's got nice features with split tunneling and so on, but way too frustrating to use regularly.

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.