**Gmail is the obvious privacy disaster that most people should be aware of right now.**  
Gmail historically scanned inbox content to serve targeted ads. Gmail still sits inside a much larger data ecosystem. Google continues to collect cross-service signals from Search, YouTube, and other products to target ads shown inside Gmail, meaning your inbox is still part of an advertising machine even without direct content scanning.   
Your mails can also automatically be scanned by server-side AI.

**Proton Mail is better, but not perfect.**  
Proton is a good first step up. The email body and attachments are end-to-end encrypted, and even Proton cannot access them. That part is real and well documented.

But here is what a lot of people miss: subject lines are not end-to-end encrypted on Proton Mail.  
Proton confirms this directly on their own support page: "Subject lines in Proton Mail are not end-to-end encrypted, which means if served with a valid Swiss court order, we do have the ability to turn over the subjects of your messages."

There are two reasons for this. First, Proton is built on OpenPGP, where the subject line sits in the header packet, a part of the standard that is not end-to-end encrypted. Second, encrypting subjects server-side would break subject-based search entirely, since end-to-end encrypted data cannot be searched on the server.

In practice, accessing your subjects still requires a court order approved by a Swiss judge, and Swiss data privacy law makes unauthorized access extremely difficult. But the data exists, it is readable, and it can be handed over. Proton has acknowledged they are working toward encrypted subjects as encryption technology evolves.

For now, Proton recommends keeping your subject lines vague and generic.  
Server-side AI cannot scan your emails because they are end-to-end encrypted. However, it could scan the subject line.

**Tuta is the one that actually closes this gap**  
Tuta (based in Germany, fully under EU jurisdiction) encrypts everything end-to-end by default: body, attachments, subject lines, sender and recipient names, contacts, and even calendar metadata. All of it.

Tuta explicitly does not use PGP, and they explain exactly why: "PGP does not encrypt the subject line (already achieved in Tuta)". Because Tuta built their own encryption protocol rather than inheriting PGP's limitations, they were able to include subject lines in E2EE from the start.

When both parties use Tuta, nothing is visible to Tuta's servers, including the subject. There is nothing to hand over because there is nothing to read.

When you email someone outside Tuta, the recipient gets a generic notification with no real subject exposed. They access the actual message, including the real subject, through a password-protected link using a shared password you communicate separately.

The trade-offs are real: server-side search by subject is not possible since search runs locally on your device after decryption. Push notification previews of subject lines are only available on devices where you are already logged in, using local decryption.

Tuta also now offers post-quantum encryption using a hybrid protocol combining AES-256, RSA-2048 or ECC (x25519), and Kyber-1024, making it one of the few email providers already protecting against harvest-now-decrypt-later attacks.

It is not possible for server-side AI to scan your emails in Tuta, not even the subject line.

If subject line privacy matters to you, and it should because subjects often reveal more context than people realize, Tuta is the only major provider that fully solves this. Both are better than Gmail. But they are not the same thing.

Gmail scans your inbox, Proton Mail can read your subject line, and only one European provider encrypts everything by default. The technical reason why: