Superhuman acquires GPTZero, the AI detector with $30 million in annual revenue

Edward Tian built GPTZero over a college winter break. It now has more than 20 million registered users, $30 million in annual recurring revenue, and a new owner. Superhuman, the productivity company formerly known as Grammarly, has agreed to acquire GPTZero for undisclosed terms. From crashed hosting page to acquisition target Tian was a senior at Princeton when he and co-founder Alex Cui put GPTZero together. The tool did one thing. It estimated how much of a given piece of writing had been generated by AI. He posted it on a free Streamlit hosting page. Within a week, 30,000 people had shown up, and the site crashed under the load. GPTZero launched publicly in January 2023. In less than four years, it went from a student side project to a business generating $30 million in ARR. That metric measures the yearly value of a company’s recurring subscription income, so it reflects paying customers rather than curious visitors. Superhuman announced the deal on June 23, 2026. Neither side disclosed the price. PitchBook data valued GPTZero at more than $88 million. A source familiar with the matter told Fortune that the deal represented at least a 10x return on the $13.5 million the compa...