build upon vs build on

build upon and build on both are verbs.

Word	Noun	Adjective	Verb	Adverb
build upon	No	No	Yes	No
build on	No	No	Yes	No

As verbs, build upon and build on are synonyms defined as:

Other synonyms of build upon include repose on, rest on.

build upon (verb)	build on (verb)
use as a basis for theories and claims	use as a basis for theories and claims