Synapse is an open source Matrix homeserver implementation, written and
maintained by Element.

Matrix is an ambitious new ecosystem for open federated Instant Messaging and
VoIP. The basics you need to know to get up and running are:

  * Everything in Matrix happens in a room. Rooms are distributed and do not
    exist on any single server. Rooms can be located using convenience
    aliases like #matrix:matrix.org or #test:localhost:8448.
  * Matrix user IDs look like @matthew:matrix.org (although in the future you
    will normally refer to yourself and others using a 3PID: email address,
    phone number, etc rather than manipulating Matrix user IDs)