• Docs >
  • Building ExecuTorch LLaMA Android Demo App

Building ExecuTorch LLaMA Android Demo App

This app demonstrates the use of the LLaMA chat app demonstrating local inference use case with ExecuTorch.


  • Set up your ExecuTorch repo and environment if you haven’t done so by following the Setting up ExecuTorch to set up the repo and dev environment.

  • Install Java 17 JDK.

  • Install the Android SDK API Level 34 and Android NDK 25.0.8775105.

  • If you have Android Studio set up, you can install them with

    • Android Studio Settings -> Language & Frameworks -> Android SDK -> SDK Platforms -> Check the row with API Level 34.

    • Android Studio Settings -> Language & Frameworks -> Android SDK -> SDK Tools -> Check NDK (Side by side) row.

  • Alternatively, you can follow this guide to set up Java/SDK/NDK with CLI.

  • Supported Host OS: CentOS, macOS Sonoma on Apple Silicon.

Note: This demo app and tutorial has only been validated with arm64-v8a ABI, with NDK 25.0.8775105.

Getting models

Please refer to the ExecuTorch Llama2 docs to export the model.

After you export the model and generate tokenizer.bin, push them device:

adb shell mkdir -p /data/local/tmp/llama
adb push llama2.pte /data/local/tmp/llama
adb push tokenizer.bin /data/local/tmp/llama

Note: The demo app searches in /data/local/tmp/llama for .pte and .bin files as LLAMA model and tokenizer.

Build library

For the demo app to build, we need to build the ExecuTorch AAR library first.

The AAR library contains the required Java package and the corresponding JNI library for using ExecuTorch in your Android app.

Alternative 2: Build from local machine

  1. Open a terminal window and navigate to the root directory of the executorch.

  2. Set the following environment variables:

export ANDROID_NDK=<path_to_android_ndk>
export ANDROID_ABI=arm64-v8a

Note: <path_to_android_ndk> is the root for the NDK, which is usually under ~/Library/Android/sdk/ndk/XX.Y.ZZZZZ for macOS, and contains NOTICE and README.md. We use <path_to_android_ndk>/build/cmake/android.toolchain.cmake for CMake to cross-compile.

  1. Run the following command set up the required JNI library:

pushd examples/demo-apps/android/LlamaDemo
./gradlew :app:setup

This is running the shell script setup.sh which configures the required core ExecuTorch, LLAMA2, and Android libraries, builds them, and copy to jniLibs.

Build APK

Alternative 2: Command line

Without Android Studio UI, we can run gradle directly to build the app. We need to set up the Android SDK path and invoke gradle.

export ANDROID_HOME=<path_to_android_sdk_home>
pushd examples/demo-apps/android/LlamaDemo
./gradlew :app:installDebug

On the phone or emulator, you can try running the model: Android LLaMA App


Through this tutorial we’ve learnt how to build the ExecuTorch LLAMA library, and expose it to JNI layer to build the Android app.

Reporting Issues

If you encountered any bugs or issues following this tutorial please file a bug/issue here on Github.


Access comprehensive developer documentation for PyTorch

View Docs


Get in-depth tutorials for beginners and advanced developers

View Tutorials


Find development resources and get your questions answered

View Resources