Tsung is an open-source multi-protocol distributed load testing tool It can be used to stress HTTP, SOAP, PostgreSQL and Jabber/XMPP servers. Tsung (formerly known as IDX-Tsunami) is a free software released under the GPL license. The purpose of Tsung is to simulate users in order to test the scalability and performances of IP based client/server applications. You can use it to do load and stress testing of your servers. Currently, HTTP, PostgreSQL and XMPP(Jabber) protocols have been implemented and tested, but it can be easily extended. It can be distributed on several client machines and is able to simulate thousands of virtual users concurrently. Tsung is developped in Erlang, an open-source language made by Ericsson for building robust fault-tolerant distributed applications.