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Copyleaks vs GPTZero: catalog facts
Copyleaks	GPTZero
Paid A commercial service; the homepage directs organisations to request a demo.	Freemium Free scans up to 10,000 characters, with paid upgrades for advanced features.
Web	Web, Browser extension
Detects both plagiarism and AI-generated text Checks source code for plagiarism	Sentence-level highlighting rather than a single score Writing replay in Google Docs shows how a document was produced
Aimed mainly at institutions and businesses AI detection results are probabilistic and can be wrong	AI detection is probabilistic and can misclassify human writing Free scans are limited in length
Hosted service	Web application, Browser extension
Closed source	Closed source
License not stated	License not stated
Account needed	Not stated if an account is needed
Needs internet	Needs internet
Official website Full listing and sources Checked September 26, 2026	Official website Full listing and sources Checked September 26, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.