ProtonMail is an email service from Proton Technologies AG in Switzerland that is expressly designed for privacy and security with end-to-end encryption. The service can be used from a mobile app or a web interface, both with a streamlined modern interface and the ability to send encrypted messages and attachments to non-ProtonMail users for retrieval via web browser, as well as sending encrypted messages to other ProtonMail users. You can also send normal, unencrypted email from the system. (See ProtonMail support and security details for additional information.)

ProtonMail Encrypted Email 1.10.3 is a free download for iOS 10 and later (as well as Android), and the ProtonMail service is available free as donationware, limited to 500 MB of storage, 50 messages/hour and 150 messages/day.

ProtonMail Plus service, priced at €5/mo. (€48/yr.) with 5 GB of storage and custom email filters, lets you use your own email domain and raises the messaging limits. ProtonMail Visionary service, priced at €30/mo. (€288/yr.) offers 20 GB of storage, multiuser support, 10 custom domains, “unlimited” messaging and ProtonVPN service. In between is a Professional plan at €8/mo./user (€75/yr./user).

Security Features

Even your communication with non-ProtonMail users can be secure

We support sending encrypted communication to non-ProtonMail users via symmetric encryption. When you send an encrypted message to a non-ProtonMail user, they receive a link which loads the encrypted message onto their browser, which they can decrypt using a passphrase that you have shared with them. You can also send unencrypted messages to Gmail, Yahoo, Outlook and others, just like regular email. … There is nothing to install, and no encryption keys to manage, if you can use Gmail, Thunderbird, or Outlook, you can use ProtonMail.

ProtonMail Bridge 1.3.3 is an app that “runs on your computer in the background and seamlessly encrypts and decrypts your mail as it enters and leaves your computer.” Available with paid ProtonMail accounts for Macs, Linux and Windows, it supports Apple Mail, Thunderbird and Outlook. (See Introducing ProtonMail Bridge… for more details.)

ProtonMail Import-Export is a utility currently in beta testing for paid accounts: