SEMS is a media and application server for SIP based VoIP services. It shows good performance doing basic services like announcements and conference for combination with external application servers, and, thanks to its easy to use and flexible application development framework and back-to-back user agent support, application logic and media serving can be combined in the same process.

It can provide a full VoIP system together with SIP Express Router (SER). Basic applications like announcement, pre-call announcement, RBT, conference, voicemail, mailbox etc. and lots of example applications available. Scripting in python and a simple state machine description language.

Support for all commonly used free codecs (g711, gsm, iLBC, speex, adpcm, l16 etc), wideband, ZRTP encryption, SIP registrar client, XMLRPC server/client, DIAMETER client and more.

SEMS is free software (speech+beer), licensed under GPLv2+.