Maksymilian Rafailovych "Max" Levchyn (; born July 11, 1975) is an American
computer scientist and
internet entrepreneur. He is the Chief Executive of digital lending start-up
Affirm. He is also the former
chief technology officer of
PayPal, which he co-founded in 1998. As CTO he was primarily known for his contributions to PayPal's anti-fraud efforts and is also the co-creator of the Gausebeck-Levchin test, one of the first commercial implementations of a
CAPTCHA challenge response human test.