Standalone

 stand-a·lone

/ˈstandəˌlōn/

adjective

: standalone

1. (of computer hardware or software) able to operate independently of other hardware or software.

   "a stand-alone application."

not being part of a larger work or series 

For example, a fax machine is a stand-alone device because it does not require a computer, printer, modem, or other device.

single, complete by itself: Stand-alone houses have become too expensive for many people.

When spelled as a closed compound or hyphenated compound, stand-alone/standalone is an adjective.