Proton Mail

About

Proton Mail is the world's largest secure email service, developed by CERN and MIT scientists. We are open source and protected by Swiss privacy law. As a privacy-focused email service, Proton Mail uses end-to-end encryption, and offers full support for PGP and standalone email clients via Proton Mail Bridge.

It offers a Gmail-like user interface, secure compatibility with other email providers, and does not track its users. Namely, Proton Mail cannot read the content of any of its users' emails stored encrypted on our servers (this applies to attachments too).