SWsoft was a privately held server automation and virtualization software company and the parent company of Parallels.

SWsoft products included applications for operating system-level virtualization, which enables users to run multiple operating systems, including Windows, Mac OS X, Linux, and Solaris, on a single computer.

The company was founded in 1997 and maintained its headquarters in Herndon, Virginia, with additional offices throughout North America, Europe, and Asia.

Although the company’s software reportedly uses fewer system resources because it does not require each virtualized server to have an independent operating system, its overall flexibility is limited.

For example, each virtualized Virtuozzo server must have the same version of the same operating system, and when running Linux, the operating system's kernel must be modified from the standard version.