Mailman Developer Resources

Thank you for contributing to Mailman!

See the quick start.

Contributing to Mailman, step 1: Bazaar and Launchpad

Mailman's source code is published in a publicly available revision control system called Bazaar available through the code hosting and open source development service called Launchpad. On June 22, 2007, we switched from using Subversion on SourceForge to the new repository, and while the old Subversion repository will still be available read-only, no new updates will be committed to it. Hosting the source code on Bazaar provides both the core developers and unofficial third party extensions much more freedom to hack on Mailman.

Here is more detail on how to develop Mailman code using Bazaar and Launchpad.

Here are a list of important official and unofficial branches.

Contributing to Mailman, step 2: Contribution workflow process

  1. A developer has an idea for an enhancement.  They describe it here and we can discuss general design issues, coding suggestions, decomposition of work into branches, etc. For higher bandwidth discussions we can use irc (#mailman channel on irc://

  2. The Mailman community may be able to indicate in a non-binding way whether an idea is likely to be accepted, which can help the potential contributor decide to keep working with that in mind, or continue on however they like. (This being open source and bzr being a DVCS, everyone is free to do whatever they want.)
  3. If the idea is appropriate for Mailman, FSF must get copyright assignments from the developer. See below. Do this early, since it can take some time to get all the paperwork to the FSF.

Branch development guidelines

  • Branches should be self-contained:  Include documentation, a NEWS entry, and for Mailman 3, include tests.  Ideally, there would be one bug for every branch.
  • Branches should be as small as possible. The smaller the branch the easier it is to review.  For Launchpad, we have a strict 800 line diff limit on branches, since anything beyond that gets very difficult and time consuming to review.

Branch review and merge

  • When a branch is ready for review, create a merge proposal for it and email the Mailman devel list.
  • A Core Mailman developer will review the code.  (For Mailman 2.x, it will most likely be Mark.  For Mailman 3 it will be Barry.)
  • Once we've approved the branch, either Mark or Barry will merge it into the official trunks.  Currently only a few of us have write permission to the official branches.

Mailman is a GNU project with the majority of the copyrights being held by the Free Software Foundation. We therefore request that developers who contribute code, assign their copyrights in their Mailman contribution to the FSF. To do this, you first need to submit a GNU copyright assignment request form containing some basic information, and then fill out the form that the FSF sends you. Please let us know after you've sent the second form so that we can track your contribution. The FSF often doesn't tell us in a timely manner when such forms have been received.

Version-specific resources

Mailman's developers are currently focused mostly on working towards the release of Mailman 3.0.


Initiatives and proposals


People seem to have trouble figuring out where to make suggestions or feature requests. There is a suggestions page here, or you may wish to start a discussion on the mailman-developers list

Relevant RFCs, references, and standards

Here are some useful RFCs, references and drafts:

Best practices:

MailmanWiki: DEV/Home (last edited 2015-03-03 17:38:39 by msapiro)