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Delta Chat Android Client

This is the Android client for Delta Chat. It is available on F-Droid and the Google Play Store. The APK can also be downloaded from GitHub (only for experienced users).

For the core library and other common info, please refer to the Delta Chat Core Library.

Screenshot Chat List Screenshot Chat View

Check Out Repository

When checking out deltachat-android, make sure also to check out the subproject deltachat-core-rust:

  • When using Git, you can do this initially by $ git clone --recursive or later by git submodule update --init --recursive. If you do this in your home directory, this results in the folder ~/deltachat-android which is just fine.

Build Using Nix

The repository contains Nix development environment described in flake.nix file. If you don't have Nix installed, the easiest way is to use The Determinate Nix Installer which installs Nix with Flakes feature enabled out of the box and can be cleanly uninstalled with /nix/nix-installer uninstall once you don't need it anymore.

Once you have Nix with Flakes feature set up, run nix develop to start development environment shell.

Nix development environment contains Rust with cross-compilation toolchains and Android SDK. To build an APK, run:

$ scripts/
$ ./gradlew assembleDebug

Resulting APK files can be found in build/outputs/apk/gplay/debug/ and build/outputs/apk/fat/debug/.

Build Using Dockerfile

Another way to build APK is to use provided Dockerfile with Docker or Podman. Podman is a drop-in replacement for Docker that does not require root privileges.

If you don't have Docker or Podman setup yet, read how to setup Podman below. If you don't want to use Docker or Podman, read how to manually install the build environment.

First, build the image deltachat-android by running

podman build --build-arg UID=$(id -u) --build-arg GID=$(id -g) . -t deltachat-android


docker build --build-arg UID=$(id -u) --build-arg GID=$(id -g) . -t deltachat-android

Then, run the image:

podman run --userns=keep-id -it --name deltachat -v $(pwd):/home/app:z -w /home/app localhost/deltachat-android


docker run -it --name deltachat -v $(pwd):/home/app:z -w /home/app localhost/deltachat-android

You can leave the container with Ctrl+D or by typing exit and re-enter it with docker start -ia deltachat or podman start -ia deltachat.

Within the container, install toolchains and build the native library:

deltachat@6012dcb974fe:/home/app$ scripts/
deltachat@6012dcb974fe:/home/app$ scripts/

Then, build an APK:

deltachat@6012dcb974fe:/home/app$ ./gradlew assembleDebug


  • Executing ./gradlew assembleDebug inside the container fails with The SDK directory '/home/user/Android/Sdk' does not exist.:

    The problem is that Android Studio (outside the container) automatically creates a file with a content like sdk.dir=/home/username/Android/Sdk, so, Gradle-inside-the-container looks for the Sdk at /home/username/Android/Sdk, where it can't find it. You could:

    • either: remove the file or just the line starting with sdk.dir
    • or: run ./gradlew assembleDebug from outside the container (however, there may be incompability issues if different versions are installed inside and outside the container)
  • Running the image fails with ERRO[0000] The storage 'driver' option must be set in /etc/containers/storage.conf, guarantee proper operation.:

    In /etc/containers/storage.conf, replace the line: driver = "" with: driver = "overlay". You can also set the driver option to something else, you just need to set it to something. Read about possible options here.

Setup Podman

These instructions were only tested on a Manjaro machine so far. If anything doesn't work, please open an issue.

First, Install Podman.

Then, if you want to run Podman without root, run:

sudo touch /etc/subgid
sudo touch /etc/subuid
sudo usermod --add-subuids 165536-231072 --add-subgids 165536-231072 yourusername

(replace yourusername with your username). See for more information.

Install Build Environment (without Docker or Podman)

To setup build environment manually:

  • Either, in Android Studio, go to "Tools / SDK Manager / SDK Tools", enable "Show Package Details", select "CMake" and the desired NDK (install the same NDK version as the Dockerfile), hit "Apply".
  • Or read Dockerfile and mimic what it does.

Then, in both cases, install Rust using rustup and Rust toolchains for cross-compilation by executing scripts/

Then, configure ANDROID_NDK_ROOT environment variable to point to the Android NDK installation directory e.g. by adding this to your .bashrc:

export ANDROID_NDK_ROOT=${HOME}/Android/Sdk/ndk/[version] # (or wherever your NDK is) Note that there is no `/` at the end!
export PATH=${PATH}:${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/:${ANDROID_NDK_ROOT}

After that, call scripts/ in the root directory to build core-rust. Afterwards run the project in Android Studio. The project requires API 25.

With chance, that's it :) - if not, read on how to set up a proper development environment.

Install Development Environment

  1. Some libs required by Android Studio may be missing on 64 bit Linux machines Source], so for Ubuntu execute $ sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 lib32z1 libbz2-1.0:i386 and for Fedora execute $ sudo yum install zlib.i686 ncurses-libs.i686 bzip2-libs.i686.

  2. Download Android Studio from ( and unpack the archive which contains a single folder called android-studio; move this folder e.g. to ~/android-studio.

  3. To launch Android Studio for the first time, open a terminal, navigate to ~/android-studio/bin, execute ./ and use all the standard values from the wizard.

  4. Android Studio now asks you if you want to open an existing project; choose ~/deltachat-android as created in the "Build" chapter (Android Studio starts to build the project, however, there are some steps missing before this will succeed).

  5. If components are missing, click on the corresponding error message and install eg. required SDKs and the "Build-Tools" (you should also find the option at "Tools / Android / SDK Manager / SDK Platforms"). Now the build should succeed - but the app still misses the native part.

  6. Download Android NDK from NDK Archives and extract the archive containing a single folder called something like android-ndk-r23b-linux; move this folder e.g. to ~/android-ndk.

  7. Export the folder path to your environment as ANDROID_NDK_ROOT and add it to PATH. You can achieve this e.g. by adding this to your .bashrc

    export ANDROID_NDK_ROOT=${HOME}/android-ndk
    export PATH=${PATH}:${ANDROID_NDK_ROOT}/toolchains/llvm/prebuilt/linux-x86_64/bin/:${ANDROID_NDK_ROOT}

Run UI Tests and Benchmarks

  • You don't necessarily need a dedicated testing device. Backup your current account first, maybe there are some bugs in switching accounts.

  • You can run benchmarks on either an emulated device or a real device. You need at least Android 9. For better benchmark results, you should run the benchmark on a real device and make sure that the core is compiled in release mode.

  • Disable animations on your device, otherwise the test may fail: at "Developer options" set all of "Window animation scale", "Transition animation scale" and "Animator duration scale" to 0x

  • In Android Studio: "File" / "Sync project with gradle files"

  • In Android Studio: "Run" / "Edit configurations" / "+" / "Android Instrumented test": Either select a specific class or select "All in Module" / "OK" / Select your configuration in the toolbar / Click on the green "run" button in the toolbar to run the tests

Get the benchmark results

When the benchmark is done, you will get a result like MEASURED RESULTS (Benchmark) - Going thorough all 10 chats: 11635,11207,11363,11352,11279,11183,11137,11145,11032,11057. You can paste 11635,11207,11363,11352,11279,11183,11137,11145,11032,11057 into a cell in a LibreOffice spreadsheet, do "Data" / "Text to columns", choose , as a separator, hit "OK", and create a diagram.

Run online tests

For some tests, you need to provide the credentials to an actual email account. You have 2 ways to do this:

  1. (Recommended): Put them into the file ~/.gradle/ (create it if it doesn't exist):
  2. Or set them via environment variables.


The user interface classes are based on the Signal messenger.


Licensed GPLv3+, see the LICENSE file for details.

Copyright © 2022 Delta Chat contributors.