A proof of concept (POC or PoC), also known as proof of principle, is an inchoate realization of a certain idea or method in order to demonstrate its feasibility or viability. A proof of concept is usually small and may or may not be complete, but aims to demonstrate in principle that the concept has practical potential without needing to fully develop it.

A proof of value (PoV) is sometimes used along proof of concept, and differs by focusing more on demonstrating the potential customer use case and value, and is usually less in-depth than a proof of concept.

The term has been in use since 1967. In a 1969 hearing of the Committee on Science and Astronautics, Subcommittee on Advanced Research and Technology, proof of concept was defined as following:

The Board defined proof of concept as a phase in development in which experimental hardware is constructed and tested to explore and demonstrate the feasibility of a new concept.

One definition of the term "proof of concept" was by Bruce Carsten in the context of a "proof-of-concept prototype" in his magazine column "Carsten's Corner" (1989):

Proof-of-Concept Prototype is a term that (I believe) I coined in 1984. It was used to designate a circuit constructed along lines similar to an engineering prototype, but one in which the intent was only to demonstrate the feasibility of a new circuit and/or a fabrication technique, and was not intended to be an early version of a production design.

The column also provided definitions for the related but distinct terms 'breadboard' (a term used since 1940), 'prototype', 'engineering prototype', and 'brassboard'.

Sky Captain and the World of Tomorrow, 300, and Sin City were all shot in front of a greenscreen with almost all backgrounds and props computer-generated. All three used proof-of-concept short films. In the case of Sin City, the short film became the prologue of the final film.^{[citation needed]}