checkdmarc requires Python 3.

On Debian or Ubuntu systems, run:

sudo apt-get install python3-pip

Python 3 installers for Windows and macOS can be found at

To install or upgrade to the latest stable release of checkdmarc on macOS or Linux, run

pip3 install -U checkdmarc

Or, install the latest development release directly from GitHub:

pip3 install -U git+


On Windows, pip3 is pip, even with Python 3.