Buildbot is licensed under the terms of the [http://www.gnu.org/licenses/gpl-2.0.html GNU General Public License, Version 2].  See [https://github.com/buildbot/buildbot/blob/master/master/COPYING master/COPYING] and (identical) [https://github.com/buildbot/buildbot/blob/master/slave/COPYING slave/COPYING] for the license as it is considered to apply to Buildbot.

An enormous number of people have contributed to Buildbot, and each owns his or her contributions.