Criterion CheckWise AI GPTZero
CategoryAI Detection & Plagiarism CheckingAI Detection & Plagiarism Checking
In one sentenceAn independent document-analysis service that runs an AI-writing check and a similarity (plagiarism) check on the same upload.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.
Problem it solvesGives students, researchers, writers and businesses a quick, pay-per-check way to see whether a document shows AI-writing signals or closely matches existing sources, without a subscription.Helps teachers, editors and reviewers get a signal on whether submitted writing may have been produced by AI tools such as chatbots.
Free planNoYes
Developer APINoYes — docs
Open sourceNoNo
PlatformsWebWeb, Chrome extension, Google Docs add-on, API
Pricing (summary)Each account gets 1 free check (AI and similarity reports) until 1 January 2027, with no credit card. After that you buy one-time token packs: Starter $3 for 1 check, Plus $25 for 10 checks, Business $200 for 100 checks. Tokens are valid for 30 days; there is no subscription.
Checked 2026-10-19		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.
Checked 2026-10-13
Strengths
  • AI analysis and similarity check combined in one check
  • Simple per-check pricing with no subscription
  • Clear data-handling statements: own server, no training on documents, 90-day purge
  • Says plainly that AI detection is probabilistic
  • 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
  • AI detection can produce false positives and false negatives — the site says a score is an indicator, never proof
  • The size and scope of the similarity index are not described
  • No API or LMS integrations are listed
  • Purchased tokens are valid for 30 days
  • Supported languages are not stated
  • 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