GPTZero

GPTZero is an AI content detector that classifies pasted or uploaded text as human-written, AI-written, or mixed, with a companion Hallucination Detector and a separate plagiarism-check product sold alongside it. Detection covers output from ChatGPT, GPT-4/5/6, Claude, Gemini, Llama, and other large language models rather than being tuned to a single AI vendor, and the company ships a Chrome extension ("Origin") that can scan an entire web page, including inside Google Docs.

Results are presented as a document-level classification (human-only, mixed, or AI-only) with a confidence score, plus sentence-level highlighting that marks the specific passages driving the AI classification; the API separately exposes per-class probabilities. GPTZero also markets an "AI Vocabulary Scan" and a paraphraser/AI-bypasser detector aimed at catching text run through humanizing tools, and publishes a 99% accuracy figure on its homepage without a detailed independent methodology alongside it.

The product is built and marketed overwhelmingly for education: GPTZero cites over 10 million teachers and students and a partnership with the American Federation of Teachers, and its higher tier adds Canvas/Google Classroom LMS integration. Separate marketing pages also target writers and recruiters, and an Enterprise/Team option lets an organization buy multiple seats under shared credits and unified billing, but the core feature set stays oriented around classroom and academic-integrity use rather than enterprise content-compliance workflows.