ProtonMail is an end-to-end encrypted email service.

Mailpile is a webmail client with encryption and privacy features built-in. Mailpile is free and open-source software.

Hushmail is an encrypted proprietary web-based email service offering PGP-encrypted e-mail and vanity domain service.

Tutanota is an open-source end-to-end encrypted email software and freemium hosted secure email service.

Lavabit is an open-source encrypted webmail service.

Mailfence is a web-based email service that offers OpenPGP based end-to-end encryption and digital signatures.