GPTZero is an AI content detection platform built to identify text generated by large language models like ChatGPT, Claude, and Gemini. Edward Tian built the first version while a student at Princeton, launching it in January 2023 with co-founder Alex Cui; the tool went viral almost immediately as one of the first widely available AI detectors and now reports more than 10 million users, including roughly 1 million educators.
Beyond core AI detection, which the company reports at 99% accuracy in internal testing, GPTZero has expanded into a broader writing-integrity suite covering plagiarism detection, grammar checking, hallucination detection, and general writing-quality analysis. The product is available through the web app, a Chrome extension, and an API for institutions that need to screen submissions at scale.
In June 2026, Superhuman (the AI email company now under Grammarly) announced it was acquiring GPTZero, with both co-founders joining Superhuman as part of the deal. The company has said GPTZero will remain available as a standalone product for existing users while its detection capabilities are folded into Superhuman's broader authenticity tooling. The free tier covers up to 10,000 characters for unregistered users; paid personal plans start around $15 per month, with API pricing from $45 per month for higher-volume use.
