The Simplest Functional Product (SFPSFP The Simplest Functional Product (SFP) is a product which provides the absolute bare-minimum of desired functionality. Similar to a proof of concept (POC).) is a product which provides the absolute bare-minimum of desired functionality. Similar to a proof of concept (POCPOC A Proof of Concept (POC) is the implementation of a functional prototype for the purposes of validating that a technology or approach is possible.).