Mailman

Mailman provides a web‑integrated system for creating and maintaining electronic mail discussion groups and e‑newsletter distributions. Users can subscribe, manage personal settings, and retrieve messages through a browser interface, while list owners configure membership, posting policies, and delivery options. The software includes built‑in archiving of messages, automatic handling of bounced emails, content filtering, digest‑mode delivery, and spam‑filter integration.

The platform is written in Python and released under the GNU General Public License version 3, allowing anyone to host it on their own servers without subscription fees. Its open‑source nature encourages contributions from a community of developers and users, and it offers documentation, a wiki, and a code of conduct to support collaborative development and administration.

Typical users are organizations, educational institutions, and hobbyist groups that need a self‑hosted solution for managing mailing lists, providing a stable, feature‑rich alternative to proprietary services while retaining full control over data and configuration.