CounterMail is an easy-to-use web-based email and productivity management application. It allows users to manage their emails, contacts, tasks, and calendar in one place. Users can access their emails on any device and access their emails, contacts, tasks, and calendar from any location. CounterMail also offers secure encryption for emails, allowing users to keep their communications private. The application also includes a built-in email editor, allowing users to easily create and format emails. CounterMail also includes a range of tools for tracking productivity, including time tracking, task scheduling, and project management.
Too much fake confirmation from ProtonMail Spammer when real email users can't get good service in Switzerland.
Tutanota could be considered a good Countermail alternative because, like CM, they use end-to-end encryption to ensure that only encrypted versions of your data are stored. This means they can't read your emails, only you can. They also support sending encrypted emails using the PGP standard. However, Countermail and Tutanota do not have exactly the same feature set or look and feel.
Gmail
ProtonMail
Tutanota
Mailpile
Zoho Mail
Posteo
mailbox.org
Kolab Now
MsgSafe.io
SCRYPTmail
Teknik Mail
Net-C
Inboxer
Agenda Mahala
BulletMail
Vivaldi Mail
AnonyMail
Webmail.ca.za
ETHletter
Safe-mail.net
Protonmail is probably at this moment the best alternative to Countermail, depending on your needs. PM is easier to use and the Swiss laws are Swedish for privacy. But PM uses a browser based javascript to let you login to your account, only has 2 factor authentication based on mobile devices, no PGP key export / import and no calendar. (These last two things will be fixed soon). PM has a larger development team and more public exposure, so it will probably develop faster into a good long-term solution.