Telegram X — a slick experimental Telegram client based on TDLib.

This is the complete source code and the build instructions for the official alternative Android client for the Telegram messenger, based on the Telegram API and the MTProto secure protocol via TDLib.

• Telegram X on Google Play
• Subscribe to Beta
• APKs and Build Info
• Bot to verify APK hash

Build instructions

Prerequisites

• At least 5,34GB of free disk space: 487,10MB for source codes and around 4,85GB for files generated after building all variants
• 4GB of RAM
• macOS or Linux-based operating system. Windows platform is not yet supported in scripts that build native dependencies, however, it might be easy to patch them in order to make it work.

macOS

• Homebrew
• git with LFS, wget and sed: $ brew install git git-lfs wget gsed && git lfs install

Ubuntu

• git with LFS: # apt install git git-lfs
• Run $ git lfs install for the current user, if you didn't have git-lfs previously installed

Building

1. $ git clone --recursive --depth=1 --shallow-submodules https://github.com/TGX-Android/Telegram-X tgx — clone Telegram X with submodules
2. In case you forgot the --recursive flag, cd into tgx directory and: $ git submodule init && git submodule update --init --recursive --depth=1
3. Create keystore.properties file outside of source tree with the following properties:
   keystore.file: absolute path to the keystore file
   keystore.password: password for the keystore
   key.alias: key alias that will be used to sign the app
   key.password: key password.
   Warning: keep this file safe and make sure nobody, except you, has access to it. For production builds one could use a separate user with home folder encryption to avoid harm from physical theft
4. $ cd tgx
5. Run $ scripts/./setup.sh and follow up the instructions
6. If you specified package name that's different from the one Telegram X uses, setup Firebase and replace google-services.json with the one that's suitable for the app.id you need
7. Now you can open the project using Android Studio or build manually from the command line: ./gradlew assembleUniversalRelease.

Available flavors

• arm64: arm64-v8a build with minSdkVersion set to 21 (Lollipop)
• arm32: armeabi-v7a build
• x64: x86_64 build with minSdkVersion set to 21 (Lollipop)
• x86: x86 build
• universal: universal build that includes native bundles for all platforms.

Reproducing public builds

In order to verify that there is no additional source code injected inside official APKs, you must use Ubuntu 21.04 and comply with the following requirements:

1. Create user called vk with the home directory located at /home/vk
2. Clone tgx repository to /home/vk/tgx
3. Check out the specific commit you want to verify
4. In rare cases of builds that include unmerged pull requests, you must follow actions performed by Publisher's fetchPr and squashPr tasks
5. cd into tgx folder and install dependencies: # apt install $(cat reproducible-builds/dependencies.txt)
6. Follow up the build instruction from the previous section
7. Run $ apkanalyzer apk compare --different-only <remote-apk> <reproduced-apk>
8. If only signature files and metadata differ, build reproduction is successful.

In future build reproduction might become easier. Here's a list of related PR-welcome TODOs:

• Project path must not affect the resulting .so files, so user & project location requirement could be removed
• When building native binaries on macOS, .comment ELF section differs from the one built with Linux version of NDK. It must be removed or made deterministic without any side-effects like breaking native-debug-symbols.zip (or should be reported to NDK team?)
• It might be a good idea to use --build-id=0x<commit> instead of --build-id=none
• Checksums of cold APK builds always differ, even though the same keystore applied and generated inner APK contents do not differ. Real cause must be investigated and fixed, if possible.
  To generate cold build, invoke $ scripts/./reset.sh and $ scripts/./setup.sh --skip-sdk-setup.
  Warning: this will also reset changes inside some of the submodules (ffmpeg, libvpx, webp, opus and ExoPlayer)
• Move local pull requests squash-merging from Publisher to some script inside this repository to make reproduction of builds that include them easier.

PS: Docker is not considered an option, as it just hides away these tasks, and requires that all published APKs must be built using it.

Verifying side-loaded APKs

If you downloaded Telegram X APK from somewhere and would like to simply verify whether it's an original APK without any injected malicious source code, you need to get checksum (SHA-256, SHA-1 or MD5) of the downloaded APK file and find whether it corresponds to any known Telegram X version.

In order to obtain SHA-256 of the APK:

• $ sha256sum <path-to-apk> on Ubuntu
• $ shasum -a 256 <path-to-apk> on macOS

Once obtained, there are three ways to find out the commit for the specific checksum:

• Sending checksum to @tgx_bot
• Searching for a checksum in @tgx_log. You can do so without need in installing any Telegram client by using this URL format: https://t.me/s/tgx_log?q={checksum} (click to see in action). Note: unpublished builds cannot be verified this way.

License

Telegram X is licensed under the terms of the GNU General Public License v3.0.

For more information, see LICENSE file.

License of components and third-party dependencies it relies on might differ, check LICENSE file in the corresponding folder.

Third-party dependencies

List of third-party components used in Telegram X can be found here. Additionally you can check the specific commit of the third-party component used, for example, here and here.

Contributions

Telegram X welcomes contributions. Check out pull request template and guide for contributors to learn more about Telegram X internals before creating the first pull request.

If you are a regular user and experience a problem with Telegram X, the best place to look for solution is Telegram X chat — a community with over 4 thousand members. Please do not use this repository to ask questions: if you have general issue with Telegram, refer to FAQ or contact Telegram Support.