Superhuman acquires AI detection startup GPTZero

GPTZero, a three-year-old AI detection startup that Princeton graduate Edward Tian first built as a senior thesis project, has been acquired by Superhuman, the companies announced Tuesday.

Terms of the deal were not disclosed, though Tian told Business Insider that GPTZero has amassed more than 19 million registered users and $30 million in annual recurring revenue.

In 2024, Tian told TechCrunch that it was profitable. Tian and co-founder CTO Alex Cui, who has been a friend since high school, have raised a $3.5 million seed round led by Uncork Capital, followed by a $10 million Series A in June 2024 led by Footwork co-founder Nikhil Basu Trivedi, with several other notable investors including Reach Capital, Jack Altman’s Alt Capital, and Neo. All told, the company raised just $13.5 million.

Superhuman — the company founded when Grammarly bought email provider Superhuman last year and rebranded it as such — already had an AI-powered detection tool built into its platform. GPTZero’s mission is to help humans detect and defend against the decline of artificial intelligence. Grammarly’s tool aims to help users, often students, determine whether their writing looks like it was generated by artificial intelligence, and then revise it so it doesn’t. As for why Superhuman bought a competitor, Superhuman says, “Two AI detectors are better than one.”