brew update
brew install python3 libgit2 --with-libssh2
curl | python
~/.local/venvs/pipsi/bin/pip install -U
pipsi install --python=$(which python3) lancet


The following carefully crafted software packages are needed to install lancet:

  1. Python 3 (brew install python3)
  2. libgit2 with libssh2 support (brew install libgit2 --with-libssh2)
  3. pipsi (optional, see below)

Required Python packages are automatically installed.


It is suggested to use pipsi to install lancet for production use. pipsi creates and manages isolated virtual environments for specific Python packages, and then exposes the provided binaries in the global $PATH. For more information about pipsi, please check out it’s homepage.

At the time of writing, the latest release of pipsi (0.8) does not support Python 3. In order to install lancet, we need to install the development version of pipsi. This can be achieved with the following commands:

  1. Install the current stable release:

    curl | python
  2. Upgrade to the latest development release:

    ~/.local/venvs/pipsi/bin/pip install -U


lancet can be installed as any other Python package (pip, easy_install, …), but it is recommended to use pipsi.

If all the needed dependencies are installed on your system, and you have a Python 3-compatible version of pipsi, then installing is just a matter of running the following command:

pipsi install --python=$(which python3) lancet

Upgrading from a previous version

If you used pipsi to install lancet, you can upgrade to the latest version of lancet by running:

pipsi upgrade lancet

Upgrading a package installed in editable mode

When installing the package in editable mode, using pip’s -e flag, the distribution can be updated with the following command:

~/.local/venvs/lancet/bin/pip install -e path/to/the/project