The Kamailio SIP server is designed for scalability, targeting large deployments (e.g. for IP telephony operators or carriers, which have a large subscriber base or route a big volume of calls), but can be also used in enterprises or for personal needs to provide VoIP, Instant Messaging, and Presence. Kamailio is well known for its flexibility, robustness, strong security and the extensive number of features – for more information, please see:
Kamailio development was started back in 2001 by Fraunhofer Fokus, a research institute in Berlin, Germany. At that time the project name was SIP Express Router (aka SER). In 2005, a fork named OpenSER was created, which was renamed to Kamailio in July 2008 due to trademark issues. Starting in the autumn of 2008, Kamailio and SER initiated the process to merge the two projects. After the merger was complete, Kamailio became the main name of the project, being better protected in terms of trademarks.