Crossref Similarity Check vs Plagius

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.

Plagius Desktop analyzes academic papers and other documents for possible plagiarism, checking the internet or local files. It supports Word, PDF, OpenOffice, PPT, HTML, RTF, and plain-text formats. Reports can identify suspicious phrases and sources, display URLs with similarity percentages, estimate suspected-plagiarism percentages, and show analysis-quality indicators; results can be opened in a browser or exported as HTML. Its V5 AI detector analyzes paragraphs in context and returns an AI-generation probability and confidence level. The site says it recognizes signals from more than 15 models, including Gemini 3.7, GPT 5.6, and Claude 5. Professional desktop plans add local and network-share searches, batch analysis, direct URL analysis, and file comparisons. The maker says desktop analysis is performed locally, but external searches may send text fragments, usually 7 to 13 words, to search engines. AI detection may send isolated paragraphs to Plagius servers, where excerpts are deleted within up to 48 hours. A free demo runs analysis but reveals only some results. Plagius One is browser-based and initially limited to invited users. Plagius Basic costs $6.90, paid once; its license lasts 30 days and is for one Windows computer. The maker cautions that automated results need manual review and cannot alone confirm plagiarism.