Tsung is the Next Generation of a tool called IDX-Tsunami. This tool was started by Nicolas Niclausse in 2000 as a distributed jabber load stress tool for internal use at IDEALX.
It has evolved as an open-source multi-protocol load testing tool in 2001. The HTTP support was added in 2003, and this tool has been used for several industrial projects.
Since September 2004, it is developped by volunteers outside IDEALX.
Tsung is released under the General Public Licence v2.