Delta Chat
Delta Chat is a unique messaging app that works over email infrastructure — you can chat with anyone who has an email address without them needing to install any special software. It combines the convenience of instant messaging with the openness and interoperability of email, using the existing email server infrastructure. All messages are end-to-end encrypted using Autocrypt (an open standard), and no phone number or registration is required beyond any email account.
Key Features
- Works over email — Delta Chat sends messages as emails behind the scenes. Anyone with an email address is reachable, even if they don’t use Delta Chat themselves. Messages to non-Delta Chat users arrive as regular emails.
- End-to-end encryption — Uses the Autocrypt standard for automatic end-to-end encryption between Delta Chat users. No configuration needed — encryption happens in the background.
- No phone number required — Register with any existing email address. No SIM card, no phone number verification, no central server. Your identity is your email address.
- Decentralised and federated — Works with any email provider (Gmail, Outlook, self-hosted, custom domains). No single company controls the network. You own your data.
- Multi-profile and multi-device — Use multiple email accounts in one app. Seamlessly switch between work, personal, and other profiles.
- Chatmail support — Dedicated secure email relays (chatmail servers) provide faster chat-optimised email delivery with automatic encryption and no metadata leaks.
- File sharing and media — Send and receive images, documents, voice messages, and video — all delivered via the email infrastructure. No file size restrictions imposed by the app itself.
- Open standard, interoperable — Built on open email standards (IMAP/SMTP). You can use any email client to read Delta Chat messages if needed. No vendor lock-in.
Why Use Delta Chat?
Delta Chat is perfect for users who want a messenger that respects their privacy without requiring yet another account or centralised platform. Because it runs on email, you can chat with anyone — even people who don’t care about privacy apps — since messages fall back to regular email. It’s also ideal for self-hosters who already run their own mail server and want encrypted messaging without running a separate chat server.
Use Cases
- Privacy-conscious messaging without signing up for a centralised platform — use your existing email account
- Communicating with non-tech-savvy contacts who won’t install another app; messages arrive as regular emails to them
- Self-hosted email users who want encrypted instant messaging without managing a second server infrastructure
- Organisations that need federated messaging across departments using different email providers
Platform
Linux · macOS · Windows · Android · iOS
Licence
GNU General Public License v3