GPTZero
An AI detection service that estimates whether a piece of text was written by a person, by an AI model, or by a mix of both.
Plan details last verified 2026-10-13 · free plan available · developer API available
What it does
Helps teachers, editors and reviewers get a signal on whether submitted writing may have been produced by AI tools such as chatbots.
Main features
- AI Detector that highlights passages it suspects are AI-generated and gives an overall estimate
- Classifies text as human, mixed or AI, with sentence-level highlights (via the API)
- Plagiarism Check and Advanced Scan on paid plans
- Writing Replay / authorship tool that shows how a document was written, including copy-and-paste activity
- Chrome extension and Google Docs add-on, plus integrations listed for Google Classroom, Canvas and Zapier
Best use cases
- Teachers reviewing student essays as one input alongside conversation and drafts
- Editors screening freelance or contributed articles
- Writers checking their own drafts before submission
- Developers adding AI-text detection to their own platforms via the API
Getting started (beginner-friendly)
Paste text into the detector on gptzero.me; shorter texts can be scanned without signing in, and a free account is needed for longer texts. Read the highlighted sentences rather than relying only on the overall score.
Strengths
- Sentence-level highlighting shows which parts of a text drove the result
- Fits into common education and writing workflows through Chrome, Google Docs and LMS integrations
- Developer API with code samples in many programming languages
Limitations
- Detection results are probabilistic and can produce false positives; GPTZero's own site says no AI detector is 100% accurate and results should not be used as the final verdict or as the sole basis for academic or disciplinary decisions
- Scores can be less reliable on short, heavily edited or mixed human/AI texts
- Advanced features such as plagiarism checks and Writing Replay require a paid plan
Pricing (verified summary)
Free plan + paid
Free scans are available for shorter texts, with a free account needed for longer ones; paid Professional plans (monthly or annual) and Team/Enterprise plans add premium features such as advanced scans and plagiarism checks. Student and educator pricing is mentioned. Verify current plans on GPTZero's pricing page.
Last checked Oct 13, 2026. Plan details change often — always confirm on the official site before purchasing.
Platforms
Review GPTZero's privacy policy and terms before uploading student or confidential work; its developer page states that documents sent through API calls are not stored or collected.