GPTZero
Detect AI-generated content from Claude, ChatGPT, GPT-5, Gemini and more, highlight AI-generated passages sentence by sentence, and check writing quality.
About GPTZero
GPTZero is an AI content detection tool that can detect text generated by AI such as Claude, ChatGPT, GPT-5 and Gemini, and evaluate writing quality. It gives a percentage likelihood that the text was AI-generated, highlights in color the specific sentences identified as AI-generated, and offers a Chrome extension that works in Google Docs and on any web page. GPTZero is widely used in education, mainly to help teachers and students discuss academic integrity and improve writing; it also provides a developer API so detection capabilities can be integrated into other platforms. The official site explicitly warns that no AI detector is 100% accurate, results should not be used for punishment or final rulings, and detection accuracy is higher for longer texts.
Best for
Best use cases
Quickly check overall and sentence-level signs of AI generation before grading papers or assignments
See detection results and typing metrics in real time via the Chrome extension while writing assignments or documents in Google Docs
Integrate AI detection into your own education platform or content system via the API
Provision seats for a school or team in bulk, with unified billing and shared quota management
Features
AI Content Detection
Detects text generated by AI such as Claude, ChatGPT, GPT-5 and Gemini, and gives a percentage likelihood that the whole text was AI-generated.
Sentence-Level Highlighting
Highlights in color which specific sentences in the text were identified as AI-generated; the official site says its sentence-level detection is the most accurate.
Writing Quality Check
Beyond detecting AI content, it also checks writing quality to help improve your text.
Chrome Extension
A browser extension for Google Docs and the web that lets you view AI detection results and typing metrics on any page.
Developer API
Provides an AI detection API that returns the document classification (HUMAN_ONLY, MIXED, AI_ONLY), probability, confidence, and sentence-level highlight information; documents passed to API calls are not stored.
Pros
- Provides a document-level AI-generated probability and highlights in color the specific sentences identified as AI-generated
- Officially claims it has been de-biased for non-native English (ESL) writers, reducing the false positive rate to 1%
- The API does not store documents passed in calls, making it friendlier for users who care about data privacy
- Has passed a SOC 2 Type II audit and complies with education-sector data privacy requirements such as FERPA
- Offers a Chrome extension to view detection results directly in Google Docs and on any web page
Cons
- AI detection is not 100% accurate, and AI itself keeps evolving; detection results should not be used as grounds for punishment or final rulings, and are better suited as a starting point for discussion
- Officially, the model works best on longer texts and English prose; length and language affect the reliability of results