SIP Witch is released as free software under the terms of version 3 or later of the GNU General Public License (GPL).
[1] In the popular Linux distributions Ubuntu and Fedora it may be installed directly from the standard package sources.
[2][3] SIP Witch is written in the programming language C++ and uses the uCommon,[4] eXosip[5] and GNU oSIP[6] libraries.
The software enables Voice over IP as part of a self-organising Peer-to-peer telephone network.
[7] The SIP Witch is being developed since the 10th of August 2007 by David Sugar within the GNU Telephony project.