WebNN-native is a native implementation of the Web Neural Network API.

It provides several building blocks:

  • WebNN C/C++ headers that applications and other building blocks use.
    • The webnn.h that is an one-to-one mapping with the WebNN IDL.
    • A C++ wrapper for the webnn.h
  • Backend implementations that use platforms’ ML APIs:
    • DirectML on Windows 10
    • OpenVINO on Windows 10 and Linux
    • oneDNN on Windows 10 and Linux
    • XNNPACK on Windows 10 and Linux
    • Other backends are to be added

WebNN-native uses the code of other open source projects:

  • The code generator and infrastructure code of Dawn project.
  • The DirectMLX and device wrapper of DirectML project.

Build and Run

Install depot_tools

WebNN-native uses the Chromium build system and dependency management so you need to install depot_tools and add it to the PATH.


  • On Windows, you’ll need to set the environment variable DEPOT_TOOLS_WIN_TOOLCHAIN=0. This tells depot_tools to use your locally installed version of Visual Studio (by default, depot_tools will try to download a Google-internal version).

Get the code

Get the source code as follows:

# Clone the repo as "webnn-native"
> git clone https://github.com/webmachinelearning/webnn-native.git webnn-native && cd webnn-native

# Bootstrap the gclient configuration
> cp scripts/standalone.gclient .gclient

# Fetch external dependencies and toolchains with gclient
> gclient sync

Setting up the build

Generate build files using gn args out/Debug or gn args out/Release.

A text editor will appear asking build options, the most common option is is_debug=true/false; otherwise gn args out/Release --list shows all the possible options.

To build with DirectML backend, set build option webnn_enable_dml=true.

To build with OpenVINO backend, set build option webnn_enable_openvino=true.

To build with oneDNN backend, set build option webnn_enable_onednn=true.

To build with XNNPACK backend, set build option webnn_enable_xnnpack=true.


Then use ninja -C out/Release or ninja -C out/Debug to build WebNN-native.


Run tests

Run unit tests, for example ./out/Release/webnn_unittests.

Run end2end tests, for example ./out/Release/webnn_end2end_tests.


  • For OpenVINO backend, please install 2021.2 version and set the environment variables before running the end2end tests.
  • For oneDNN backend on Linux, please set the LD_LIBRARY_PATH environment variable to the out folder before running the end2end tests, e.g. LD_LIBRARY_PATH=./out/Release ./out/Release/webnn_end2end_tests.


Apache 2.0 Public License.