Delta Chat

Delta Chat looks and feels like other popular messenger apps, but does not involve centralized control, tracking or selling you, friends, colleagues or family out to large organizations. "Privacy by Design" has never been more fun.

Delta Chat taps into the largest, most diverse, most open and decentralized communication system ever created: the existing e-mail server network. Delta Chat requires no additional server-side infrastructure. Just use a standard e-mail account and start chatting with any of your e-mail contacts, whether they have installed Delta Chat or not.

Technically, Delta Chat is an e-mail application with a modern chat interface. E-Mail in a new dress if you will. Chat and contact data remain on your devices. No uploads of Addressbook, calendar or other personal data. There simply are no Delta Chat servers where anything could be uploaded to. Privacy by design.

Use Delta Chat with anyone out of billions of people: just use their e-mail address. Recipients will see a simple e-mail and may directly reply with their own e-mail app. They don't need to install Delta Chat, visit websites or sign up anywhere. If you send a picture or other media to a Chat group your chat recipients will see a nice regular e-mail with an attachment. If they send a message and attachments back, you will see the media in your Chat for this contact.

Delta Chat sends e-mails using your e-mail account and provider of choice. You can change mobile numbers without any trouble or even work without any SIM card at all. You can export all your Chat data on one device, import it on a new device and happily continue chatting. Not requiring mobile numbers avoids cell-tower and other tracking. Privacy by Design.

You can even host an optimized chatmail server yourself: https://github.com/deltachat/chatmail