Is there such a thing as an "independent code review", I would be perfectly happy to give an independent auditor access to my source code??? They could verify

Is there such a thing as an "independent code review", I would be perfectly happy to give an independent auditor access to my source code??? They could verify it works, that it will preform at scale, and that it doesn't have security vulnerabilities. But I wouldn't want to show that source code to a client who would potentially build the same product themselves.