As an equally secure (perhaps more secure?) solution, try this:
1. Host your contacts on your NAS (I use Synology's Contacts app)
2. Use a WebDAV app to sync to your mobile (I use Contact Sync on Android - paid), and
3. Use open source CalDavSynchronize to sync to your desktop Outlook client (if you use it)

The UX is not perfect if you prefer ProtonMail's webmail or app on Android... but...
I wholeheartedly agree with the many other posters who have highlighted the pace of new feature delivery at ProtonMail is incredibly slow...

The solution described above will provide a secure, reliable, and private solution TODAY.

This is the one thing stopping a full migration to ProtonMail for me. Need my contacts synced between desktop and mobile.

Yes please! and specifically an android app for contacts.

Integrating/syncing Proton contacts with existing Google contacts app would likely not provide any additional privacy than just using the Google app itself. Would prove more beneficial for standalone open-source Proton Contacts app that integrates with a privacy oriented phone calling app for those not using Google service, or looking to leave it behind. Same for iOS.

This goes all way back to 2015. It has been almost 7 years since ProtonTeam first commented on it.
4 years after in 2019 it was flagged as planned.
Now almost 3 years later, it still hasn't been implemented.
It's the 5th highest voted feature.
Come on ProtonTeam. Contacts is an important thing, not just as an in-mail widget.

This feature is a game changer. Please add it asap.

[From a paid user who just switched and is now thinking of going elsewhere...] The status of this says "Planned" as of Jan 10 2019. That is almost three years ago!! This is a critical requirement for this app to be viable. Requiring the user to maintain two contact lists is just not realistic and is driving against acceptance of Proton.

I concur. As much as a LOVE ProtonMail and all Proton products, if a user completely migrates to ProtonMail, they will be unable to use Siri on iOS for phone calls. Name resolution will not work when for incoming calls, and more. I'm sure there is some technical reason (likely security concerns) about integrating natively into iOS and MacOS, however these are normal modern functions in today's world. We need them! Thanks.

And also change notifications to not use google services

If you added a mobile Contact app, or at least the ability to sync-back-and-forth from ProtonMail, your user base would increase dramatically. Coming from a paid (Plus) user, considering (Professional), I can't pull the trigger yet. My wife would hate the contact non-mgmt.

Currently, all your users are the die-hard "privacy or death" users who can survive the inconvenience of contact non-mgmt. If you added a contact app, you would get the multitudes of "privacy preferred" users.

There's tons more of those privacy-preferred peeps out there who can't live without a contact app.

A have already migrated all my mail from gmail to the ProtonMail, it is fine, but I can not do the same with my contacts from iOS/gmail - they sync. I would like the ProtonMail Contacts will be main the place where my addresses/phones are preserved. And when I can sync the ProtonMail Contacts with iOS contacts , I will remove all conntacts from my gmail/iOS.

that's a top priority indeed

Left google service behind finally. so sad this feature is not implemented yet. pls dev. add this now :)

It would be great to be able to synchronize my ProtonMail contacts with my android phone. Currently, when I get a new contact, I have to save it twice!

This is an important functionality for both desktop and iOS app. ProtonMail Contacts needs to stay automatically synched with my Apple Contacts.

I am almost ready to buy proton as my main mail but this is really a blocker for me. I already need to stay with MS for the OneDrive but if I can't sync my contacts with my phone, it will not work. What's ETA of this feature?

Proton, any news on when this will be released? It's basic functionality.

Hello,

I agree with what is said here:

it would be fantastic if we could use ProtonContact as our contacts repository, instead of Gmail on Android.

Thinking that a US company can access all my contacts makes me sick.

I've started to migrate all my contacts from Gmail to ProtonMail. But I cannot get rid of Gmail, because there is no way to synchronize the Android contact application with ProtonMail.

Please note:

(1) technically speaking, I don't know how difficult it is to allow contacts synchronization with something other than Gmail on Android. It may not be possible.

(2) if it is possible to do so with Apple phones, I'll get an iPhone.

How can I sync the contacts in my ProtonMail contacts database automatically update my iphone contacts file? I don't think you do that. I want to be able to search phone numbers from one place since I am transitioning from gmail to protonmail.

So far I'm really pleased with the Proton team tools. The basics include: email, calendar, and contacts. Since Contacts are already built into both the email and calendar, PLEASE bump-out the Contacts as a third-pillar separate but integrated app. That would be a complete suite IMHO. Since you're working on syncing with phone contacts anyway, if we use the ProtonContacts we will no longer need the other unsafe Contacts manager apps! PLEEZE? Thank you!