Installing and running Mailman 3

Copyright (C) 2008-2017 by the Free Software Foundation, Inc.


For the Core, Python 3.5 or newer is required. It can either be the default ‘python3’ on your $PATH or it can be accessible via the python3.5 or python3.6 binary. If your operating system does not include Python 3, see for information about downloading installers (where available) and installing it from source (when necessary or preferred). Python 2 is not supported by the Core.

You may need some additional dependencies, which are either available from your OS vendor, or can be downloaded automatically from the Python Cheeseshop.


The documentation for Mailman 3 is distributed throughout the sources. The core documentation (such as this file) is found in the src/mailman/docs directory, but much of the documentation is in module-specific places. Online versions of the Mailman 3 Core documentation is available online.

Also helpful might be Mark Sapiro’s documentation on building out the server.

Get the sources

The Mailman 3 source code is version controlled using Git. You can get a local copy by running this command:

$ git clone

or if you have a GitLab account and prefer ssh:

$ git clone

Running Mailman 3


The Mailman command line interface requires a properly configured UTF-8 locale. This is because the Core is implemented in Python 3 and uses the click command line argument parsing library. Generally this will not be an issue since your shell is probably set up correctly. However, in certain environments such as init scripts and cron scripts, your locale may not be UTF-8 compatible. This can cause Mailman to mysteriously fail to run (since often, proper logging may also not be set up). If you’re seeing weird behavior in these types of environments, be sure they are UTF-8 compatible, e.g. by setting export LANG=en_US.UTF-8.

You will need to set up a configuration file to override the defaults and set things up for your environment. Mailman is configured using an “ini”-style configuration system. Usually this means creating a mailman.cfg file and putting it in a standard search location. See the configuration documentation for details.

By default, all runtime files are put under a var directory in the current working directory.

Run the mailman info command to see which configuration file Mailman is using, and where it will put its database file. The first time you run this, Mailman will also create any necessary run-time directories and log files.

Try mailman --help for more details. You can use the commands mailman start to start the runner subprocess daemons, and of course mailman stop to stop them.

Note that you can also run Mailman from one of the virtual environments created by tox, e.g.:

$ tox -e py35-nocov --notest -r
$ .tox/py35-nocov/bin/mailman info

Mailman Shell

This documentation has examples which use the Mailman shell to interact with Mailman. To start the shell type mailman shell in your terminal.

There are some testings functions which need to be imported first before you use them. They can be imported from the modules available in mailman.testing. For example, to use dump_list you first need to import it from the mailman.testing.documentation module.

The shell automatically initializes the Mailman system, loads all the available interfaces, and configures the Zope Component Architecture (ZCA) which is used to access all the software components in Mailman. So for example, if you wanted to get access to the list manager component, you could do:

$ mailman shell
Welcome to the GNU Mailman shell

>>> list_manager = getUtility(IListManager)