Proton is a tool for use with the Steam client which allows games which are exclusive to Windows to run on the Linux operating system. It uses Wine to facilitate this.

Most users should use Proton provided by the Steam Client itself. See this Steam Community post for more details.

The source code is provided to enable advanced users the ability to alter Proton. For example, some users may wish to use a different version of Wine with a particular title.

The changelog is available on our wiki.

Acquire Proton's source by cloning https://github.com/ValveSoftware/Proton and checking out the branch you desire.

You can clone the latest Proton to your system with this command:

git clone --recurse-submodules https://github.com/ValveSoftware/Proton.git proton

Be sure to update submodules when switching between branches:

git checkout experimental_6.3
git submodule update --init --recursive

If you want to change any subcomponent, now is the time to do so. For example, if you wish to make changes to Wine, you would apply them to the wine/ directory.

Most of Proton builds inside the Proton SDK container with very few dependencies on the host side.

You need either a Docker or a Podman setup. We highly recommend the rootless Podman setup. Please refer to your distribution's documentation for setup instructions (e.g. Arch Podman / Docker, Debian Podman / Docker).

We provide a top-level Makefile which will execute most of the build commands for you.

After checking out the repository and updating its submodules, assuming that you have a working Docker or Podman setup, you can build and install Proton with a simple:

make install

If your build system is missing dependencies, it will fail quickly with a clear error message.

After the build finishes, you may need to restart the Steam client to see the new Proton tool. The tool's name in the Steam client will be based on the currently checked out branch of Proton. You can override this name using the build_name variable.

See make help for other build targets and options.

mkdir ../build && cd ../build
../proton/configure.sh --enable-ccache --build-name=my_build

Running configure.sh will create a Makefile allowing you to build Proton. The scripts checks if containers are functional and prompt you if any host-side dependencies are missing. You should run the command from a directory created specifically for your build.

The configuration script tries to discover a working Docker or Podman setup to use, but you can force a compatible engine with --container-engine=<executable_name>.

You can enable ccache with --enable-cache flag. This will mount your $CCACHE_DIR or $HOME/.ccache inside the container.

--proton-sdk-image=registry.gitlab.steamos.cloud/proton/soldier/sdk:<version> can be used to build with a custom version of the Proton SDK images.

Check --help for other configuration options.

NOTE: If SELinux is in use, the Proton build container may fail to access your user's files. This is caused by SELinux's filesystem labels. You may pass the --relabel-volumes switch to configure to cause the container engine to relabel its bind-mounts and allow access to those files from within the container. This can be dangerous when used with system directories. Proceed with caution and refer your container engine's manual.

make

Important make targets:

make install - install Proton into your user's Steam directory, see the install Proton locally section for details.

make redist - create a redistribute build (redist/) that can be copied to ~/.steam/root/compatibilitytools.d/.

make deploy - create a deployment build (deploy/). This is what we use to deploy Proton to Steam users via Steamworks.

make module=<module> module - build both 32- and 64-bit versions of the specified wine module. This allows rapid iteration on one module. This target is only useful after building Proton.

make dxvk / make vkd3d-proton - rebuild DXVK / vkd3d-proton.

Steam ships with several versions of Proton, which games will use by default or that you can select in Steam Settings' Steam Play page. Steam also supports running games with local builds of Proton, which you can install on your machine.

To install a local build of Proton into Steam, make a new directory in ~/.steam/root/compatibilitytools.d/ with a tool name of your choosing and place the directory containing your redistributable build under that path.

The make install target will perform this task for you, installing the Proton build into the Steam folder for the current user. You will have to restart the Steam client for it to pick up on a new tool.

A correct local tool installation should look similar to this:

compatibilitytools.d/my_proton/
├── compatibilitytool.vdf
├── filelock.py
├── LICENSE
├── proton
├── proton_dist.tar
├── toolmanifest.vdf
├── user_settings.sample.py
└── version

To enable your local build in Steam, go to the Steam Play section of the Settings window. If the build was correctly installed, you should see "proton-localbuild" in the drop-down list of compatibility tools.

Each component of this software is used under the terms of their licenses. See the LICENSE files here, as well as the LICENSE, COPYING, etc files in each submodule and directory for details. If you distribute a built version of Proton to other users, you must adhere to the terms of these licenses.

Proton can be tuned at runtime to help certain games run. The Steam client sets some options for known games using the STEAM_COMPAT_CONFIG variable. You can override these options using the environment variables described below.

The best way to set these environment overrides for all games is by renaming user_settings.sample.py to user_settings.py and modifying it appropriately. This file is located in the Proton installation directory in your Steam library (often ~/.steam/steam/steamapps/common/Proton #.#).

If you want to change the runtime configuration for a specific game, you can use the Set Launch Options setting in the game's Properties dialog in the Steam client. Set the variable, followed by %command%. For example, input "PROTON_USE_WINED3D=1 %command%" to use the OpenGL-based wined3d renderer instead of the Vulkan-based DXVK renderer.

To enable an option, set the variable to a non-0 value. To disable an option, set the variable to 0. To use Steam's default configuration, do not specify the variable at all.

All of the below are runtime options. They do not effect permanent changes to the Wine prefix. Removing the option will revert to the previous behavior.