Protonmail supports setting up 2fa. Just set it up with your yubikey like I have.

https://protonmail.uservoice.com/forums/284483-protonmail/suggestions/43399935-proton-video-calling If you like this, You will probably like this too!

I would upgrade if you had this option - you are losing money and support.

The dismal response from ProtonMail in relation to the highly demanded U2F/FIDO2 support means I wont be financially supporting them with a renewed membership at my next renewal.

I suggest all other users vote with their wallets also, as ProtonMail wont change their stance on this as long as you're all still paying for this lacklustre service.

Lack of U2F support is a JOKE, how a service advertising as "secure" can still lay that it will be implemented for such a long time? I understand that domain unification is necessary for that, but for me it is last paid subscription in protonmail. For me it seems like money making features like drive or calendar are way more important for pm management, but making a "donkeys" out of the users&community is unacceptable

I have a response from ProtonMail and they said they are not working on it. I don't think we should expect it in the coming years.
When I asked them directly "are you currently working on implementing it?", that's what I got:

"Unfortunately, we are not actively working on developing this feature, as our current main focus is toward the ProtonDrive and ProtonCalendar apps."

It would be great to have.
Though, there is no need to be sarcastic, polemic, and rude. If I consider a feature as needed for my requirements, before buying service I can check if not reported in the product details.
Therefore I vote for the idea, not for the useless polemic message.

U2F/FIDO support is the one thing that keeps me from using proton as my primary email

There's no need to be rude.

Enable compatibility for hardware keys as yubico.

I can't upvote this. How ever this feature SHOULD BE PRIORITY FOR ANY PRIVACY APP. Please get it sorted guys. Keep it up.

Would propose to change the subject title to "U2F/FIDO2 support". Would be more appropriate, especially crucial when we would like to stick with free and open-source software, standards, etc. There is certainly FIDO Alliance at https://fidoalliance.org/ where these new standards are available. Nowadays FIDO2 https://fidoalliance.org/fido2/ , https://en.wikipedia.org/wiki/FIDO2_Project is used. In general, we are speaking about HSM (https://en.wikipedia.org/wiki/Hardware_security_module , https://www.cryptomathic.com/news-events/blog/understanding-hardware-security-modules-hsms) support with nowadays standards, currently FIDO2 and from former times also U2F (https://en.wikipedia.org/wiki/Universal_2nd_Factor). Today we have also CloudHSM (e.g. Amazon https://aws.amazon.com/cloudhsm/ , Google https://cloud.google.com/security-key-management , IBM https://cloud.ibm.com/catalog/infrastructure/hardware-security-module), but also software defined HSM, e.g. Krypton (U2F, https://krypt.co/ , https://alternativeto.net/software/krypton/).

Love ProtonMail. Even have the paid version. Hate not being able to use my YubiKey for 2FA with ProtonMail. C'mon guys! Get with it!

YubiKey is not as safe as open source alternatives like Solo, but yes, I want U2F/FIDO2 support.

This is essential. It's the only 2FA method that

1) doesn't require a mobile phone with a charged battery and a working mobile signal and/or internet connection
2) doesn't require drivers
3) doesn't require a special app
4) protects against man-in-the-middle attacks
5) is incredibly easy to take with you
6) you are likely to always have with you since you leave the house with your keys (right?)
7) is insanely quick and easy to use
8) doesn't pose any risks if you were to lose it since it's not tied to your person, identities, or accounts
9) is durable
10) works anywhere: USB-A, USB-C, Lightning, and NFC
11) you can have a backup of (most services, except Twitter, support registration of multiple U2F keys

Why this is still not supported is beyond me.

FIDO2 U2F is a running joke with ProtonMail, I doubt they will ever support it.

This should be consolidated with request for FIFO2 U2F Security Key Support for MFA (https://protonmail.uservoice.com/forums/284483-protonmail/suggestions/36590311-fifo2-u2f-security-key-support-for-mfa). U2F would allow for Yubikey and other standards supporting 2FA devices to be used.

I'd like to see this expanded BEYOND Yubikey to FIDO2... Any USB security key should work as a U2F. Please.

Dont understand how u2f is still not supported - literally boggles my mind.

Makes 2F vastly more convenient for users while maximizing security.