Installing Ray

Ray should work with Python 2 and Python 3. We have tested Ray on Ubuntu 14.04, Ubuntu 16.04, Ubuntu 18.04, MacOS 10.11, 10.12, 10.13, and 10.14.

Latest stable version

You can install the latest stable version of Ray as follows.

pip install -U ray  # also recommended: ray[debug]

Trying snapshots from master

Here are links to the latest wheels (which are built off of master). To install these wheels, run the following command:

pip install -U [link to wheel]
Linux MacOS
Linux Python 3.7 MacOS Python 3.7
Linux Python 3.6 MacOS Python 3.6
Linux Python 3.5 MacOS Python 3.5
Linux Python 2.7 MacOS Python 2.7

Building Ray from source

If you want to use the latest version of Ray, you can build it from source. Below, we have instructions for building from source for both Linux and MacOS.


To build Ray, first install the following dependencies. We recommend using Anaconda.

For Ubuntu, run the following commands:

sudo apt-get update
sudo apt-get install -y build-essential curl unzip psmisc python # we install python here because python2 is required to build the webui

# If you are not using Anaconda, you need the following.
sudo apt-get install python-dev  # For Python 2.
sudo apt-get install python3-dev  # For Python 3.

pip install cython==0.29.0

For MacOS, run the following commands:

brew update
brew install wget

pip install cython==0.29.0

If you are using Anaconda, you may also need to run the following.

conda install libgcc

Install Ray

Ray can be built from the repository as follows.

git clone

# Install Bazel.

cd ray/python
pip install -e . --verbose  # Add --user if you see a permission denied error.

Alternatively, Ray can be built from the repository without cloning using pip.

pip install git+

Test if the installation succeeded

To test if the installation was successful, try running some tests. This assumes that you’ve cloned the git repository.

python -m pytest -v python/ray/tests/

Cleaning the source tree

The source tree can be cleaned by running

git clean -f -f -x -d

in the ray/ directory. Warning: this command will delete all untracked files and directories and will reset the repository to its checked out state. For a shallower working directory cleanup, you may want to try:

rm -rf ./build

under ray/. Incremental builds should work as follows:

pushd ./build && make && popd

under ray/.