Cryoserver - Cryoserver is an all-in-one email archiving solution that empowers you to preserve your email in a tamper-evident archive, making you transform your data into a useful archive for everyday use.

ProtonMail - Secure email with absolutely no compromises. Get your free encrypted email account today.

Gmvault - Backup the emails in your Gmail account.

Sfletter - SFLetter.com protects your message and attachments by one click. Email protection from interception and unauthorized actions of the recipient.

imapsync - Console-based utility for migrating IMAP mailboxes.

Tutanota - Get your encrypted mailbox for free.