Installing ESPEI from PyPI (by pip install espei) is not supported. Please install ESPEI using Anaconda package manager. If you do not have Anaconda installed, we recommend you download and install Miniconda3. Optionally, you may also be want to install JupyterLab at the same time.

conda install -c conda-forge espei jupyterlab

Development versions

To make changes to the ESPEI source code, the development version must be installed. If you’ll need to make changes to pycalphad simultaneously, follow the instructions to install the development version of pycalphad first.

We recommend that users interested in developing packages work in a Conda virtual environment. The steps below will create an environment called espei-dev, which can be entered using conda activate espei-dev. The environment name is arbitrary - you can use whatever name you prefer. If you already have an environment, use conda env update ... instead of conda env create ... when following the steps below.

ESPEI uses Git and GitHub for version control. Windows users: if you do not have a working version of Git, download it here first.

To install the latest development version of ESPEI, use Anaconda to install the required dependencies using the environment-dev.yml file found in ESPEI’s repository, then install ESPEI as editable using pip.:

git clone
cd espei
conda env create -n espei-dev --file environment-dev.yml
conda activate espei-dev
pip install --no-deps -e .

Optionally, you may also be want to install JupyterLab. Each environment needs its own copy of JupyterLab, so you will need to install it even if it is already installed in your base environment. You can install it to your espei-dev environment by running

conda install -n espei-dev jupyterlab

Every time you open a new terminal window, you start in the base environment. You can activate your espei-dev environment by running

conda activate espei-dev

and return to your base environment by running

conda deactivate espei-dev

With the development version installed and your environment activated, you can run the automated tests by running


If the test suite passes, you are ready to start using the development version or making changes yourself! See the guide for contributing to ESPEI to learn more. If any tests fail, please report the failure to the ESPEI issue tracker on GitHub.

To upgrade your development version to the latest version, run git pull from the top level ESPEI directory (the directory containing the file).