Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser cl…

Otr.to is a browser based chat client.

Zulip is a chat and collaborative software.

Kolab Now is a web-based email and groupware service, based completely on free and open-source software.

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