Delta Chat

Delta Chat is a FOSS, decentralized and secure instant messaging app based on email protocols. Delta Chat feels like Whatsapp or Telegram but you can also use and regard it as an e-mail app. You may use classic e-mail servers and an existing e-mail account, without the need to sign up to any platform. Your messages will be displayed on other users’ email clients. When they email you back, you will see their reply in the same chat. If you don’t want your messages/emails to be sent from your own email address, you can also send them anonymously from a public “chatmail server” (minimal e-mail servers designed for fast and secure operations).