NEW YORK: Superhuman, the productivity platform formerly known as Grammarly, has agreed to acquire GPTZero, an AI content detection startup, the companies announced Tuesday.
The acquisition strengthens Superhuman’s push into AI authenticity tools as AI-generated content proliferates across the internet.
Financial terms were not disclosed. According to PitchBook data cited in multiple reports, GPTZero is valued at over $88 million. GPTZero has more than 19 million registered users and generates $30 million in annual recurring revenue, according to founder Edward Tian.
GPTZero was co-founded in 2023 by Tian and Alex Cui, who were then students at Princeton University.
Tian, now 26, built the original detection tool as his senior thesis project before it went viral . The startup has raised $13.5 million in funding from investors including Uncork Capital, Neo, Footwork and Jack Altman.
The acquisition deepens Superhuman’s existing authenticity tools, which include an AI detector and Authorship, a product that helps writers verify their work. GPTZero’s suite includes AI detection, hallucination detection, plagiarism checking, citation verification, AI Vision and Replay authorship tracking.
The companies said GPTZero will be integrated into Superhuman Go, an AI assistant that works across one million apps and websites. GPTZero will also continue to operate as a standalone product.
“As part of the Superhuman AI productivity platform, we’re building an authenticity layer, and GPTZero accelerates our vision,” Superhuman CEO Shishir Mehrotra said in a statement. “Together, we’re bringing the most trusted writing tool and the most trusted AI detector into one platform”.
Mehrotra told Business Insider that the decision to acquire GPTZero was driven by the talent first. “When you’re buying a business like this, the people come first,” he said . Tian and Cui will join Superhuman to lead a team focused on authenticity, along with GPTZero’s 30 employees.
The acquisition marks Superhuman’s fourth major deal, following its purchases of productivity assistant Coda, the email app Superhuman (for which it is now named), and AI spreadsheet tool Rows.
Mehrotra said demand for AI detection tools is especially critical in education, which accounts for roughly one-third of the more than $700 million in annual revenue generated by Grammarly. Professional users in fields such as consulting, recruiting and journalism account for the remainder.
According to Superhuman, approximately 50% of articles published on the internet are primarily AI-generated — equal to the number written by humans. The company said AI content detection is becoming increasingly important as readers and writers seek transparency about content origin.
Superhuman has 40 million daily active users and operates across one million apps and websites. The company rebranded from Grammarly after acquiring the Superhuman email app in 2025.
