Crossref Similarity Check vs Quetext AI Detector

Crossref Similarity Check is a paid plagiarism-screening service for Crossref members. It compares submitted manuscripts with academic publications and general web content, using Turnitin’s iThenticate software. Reports provide a Similarity Score and highlight matching passages for editorial review. Crossref says the comparison database contains over 78 million full-text scholarly content items. Editors can submit manuscripts in iThenticate or through a manuscript system using the API, then receive an immediate report describing potential matches and overlap. Membership includes read-only database access, discounted checking fees, unlimited organizational users, and enhanced text matches in Document Viewer. Participation requires Crossref membership, active publication of DOI-assigned content, and full-text URLs in metadata. The annual service fee is $40 a year, representing 20% of the membership fee. Per-document checking is free for the first 100 documents yearly, then volume-tier charges apply to documents up to 25,000 words.

Quetext AI Detector analyzes writing for signs of AI-generated text, including text associated with ChatGPT, GPT-5, Claude, Gemini, and Llama. It examines writing patterns, perplexity, and burstiness, then presents line-by-line results with a confidence score. The same scan checks for plagiarism. Quetext cautions that short phrases can be difficult to assess and that longer, structured text works better.

The free plan includes AI detection and plagiarism checks for up to 1,000 words, plus Summarizer and Humanizer limits of 2,000 words. AI Detector Only costs $7.99 a month, billed annually, and includes 50,000 words per month, reports, and API access. The Chrome extension checks webpages, Google Docs, WordPress, and plain HTML. The API accepts text or files and returns plagiarism and AI scores, with integrations described for Canvas, Blackboard, and custom portals. Reports can be downloaded or shared as PDFs. Quetext’s privacy policy says submitted content and usage data may be used for AI training and quality processes by default; it offers an opt-out for future inclusion of identifiable personal data.