As of version 2.0 (2017) keystrokes, mouse movements, and clipboard contents are sent via an encrypted SSL network connection.

TCP/IP communications (default port 24800[6]) are used to send mouse, keyboard, and clipboard events between computers in Synergy 1.

The first incarnation of Synergy was CosmoSynergy, created by Richard Lee and Adam Feder then at Cosmo Software, Inc., a subsidiary of SGI (née Silicon Graphics, Inc.), at the end of 1996.

They wrote it, and Chris Schoeneman contributed, to solve a problem: most of the engineers in Cosmo Software had both an Irix and a Windows box on their desks, and switchboxes were expensive and annoying.

The original version of Synergy had not been updated for a notable length of time (as of 6 June 2010, the latest release was 2 April 2006).