GPTZero

GPTZero is the leading AI detection software: It identifies text generated by large language models (LLMs) like ChatGPT, Gemini, and Claude with high-accuracy sentence-by-sentence analysis.

GPTZero is a premier AI content detector, launched in January 2023 by Princeton student Edward Tian, specifically to combat AI-generated academic plagiarism and maintain authentic human writing. The platform uses a proprietary, multi-step algorithm to detect content from major LLMs (e.g., GPT-4, Llama) and claims 99% accuracy. It has scaled rapidly: serving over 10 million users and integrating with 3500+ colleges and 100+ organizations across education, publishing, and hiring sectors. The tool provides both an overall AI score and granular sentence-level detection, moving beyond simple binary classification.

https://gptzero.me