Delta Chat

Delta Chat looks like a conventional messenger, but its transport is based on interoperable chatmail and e-mail protocols rather than a single company’s private messaging network. A new user can accept the automatically selected chatmail relay, choose another, or configure a compatible e-mail account. No phone number is required.

This page covers Android version 2.64.0 and the help bundled with that exact source release. We did not create an account on a public relay or test calls across different network conditions.

Chatmail first, classic e-mail as an option

With the default setup, the app creates a chatmail profile and discovers relays from a fixed list of 17 community-operated candidates. During setup it opens TCP connections to their port 443 endpoints and takes the first response; an invitation can add the inviter’s relay too. The client later adds randomly selected relays until the profile has three. Messages can arrive through all configured relays, so setup exposes the connecting IP to multiple independent operators rather than only one. Relays hold messages temporarily while recipients are offline. Contact names, avatars and group state live on the devices rather than as a permanent public profile on a central social network.

Adding a contact normally means scanning an invitation QR code or opening an invitation link. That verified setup establishes encryption for the chat. Current Delta Chat clients on default chatmail profiles send end-to-end encrypted messages.

Classic e-mail compatibility changes that boundary. If you configure a traditional e-mail account, Delta Chat can receive or send ordinary mail to people using other mail apps, and those messages may be unencrypted; Delta Chat marks them with an e-mail icon. The bundled help says simultaneous use of that address in another mail client is not supported, rather than merely discouraged.

More than text messages

Delta Chat supports groups, disappearing messages and multiple devices. A second device can be added by QR code over the local network, or through a manual backup. Voice and video calls are offered only in one-to-one encrypted chats on Android 8.0 or later. WebRTC uses all ICE transport types, so a peer can learn the device’s IP address; if a chosen relay supplies no TURN server, the client falls back to turn.delta.chat.

Location streaming is an experimental feature under Advanced settings and starts disabled. Its bundled maps.xdc viewer is allowed to load map tiles from OpenStreetMap. WebXDC apps shared inside ordinary chats—for example, a game, editor or poll—otherwise do not receive general network access.

Version 2.64 added pinned messages, a “Sending…” notification that lets large messages continue in the background, and an app gallery flow. It also improved relay selection and fixed rotated video and animated WebP files. These are upstream release notes, not claims from our own call or media testing.

Weekly statistics are optional and sent only after the user enables them, but they are pseudonymous, not anonymous: the report carries a persistent stats_id, is sent as a chat message to self_reporting@testrun.org, and can include contacts’ last-online values. Our APK scan found no known tracker SDKs.

Permissions and this particular build

The manifest is broad because the same app covers camera images, calls, audio, location sharing, local-network device transfer, files and notifications. Android still asks for sensitive runtime permissions when the relevant feature is used. REQUEST_INSTALL_PACKAGES lets the app hand an APK received in a chat to Android’s installer; this F-Droid flavour does not enable the Google Play flavour’s self-updater.

This F-Droid flavour has no Google push service. It therefore enables a foreground “reliable service” by default, with a persistent notification, to keep its network connections available in the background. The Google Play flavour uses package chat.delta, while this file uses com.b44t.messenger, so they can be installed side by side rather than updating one another.

F-Droid distributes Delta Chat as CPU-specific files. The copy here is the 64-bit ARM split, not a universal APK, so it will not install on 32-bit-only or x86 devices even though the upstream project builds other variants.

About this file

• Version 2.64.0, build 7592, is 27.0 MB and needs Android 5.0 or later.
• The APK’s SHA-256 is 1445e1a97e808f4bb0f8581adb77ba4c7c424a686e2fa1f729db5c8144c0122e, matching F-Droid’s signed index. F-Droid signs this build.
• The Android client is GPL-3.0-or-later. Delta Chat is a community project, not a service operated by this site.

CPU types in this build: arm64-v8a (64-bit ARM, almost every phone since 2017).

Versions currently kept in the F-Droid repository. We host and check only the newest one. Full changelog.