Crossref Similarity Check vs PlagiarismSearch

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.

PlagiarismSearch checks submitted writing against selected web, archived, publication, academic, and enabled organizational sources. Its reports identify matching or similar passages, link those passages to detected sources, and provide a similarity report. An AI writing feature gives probability indicators for the full text and individual passages, highlighting passages for review. The service also lists paper analysis, readability, and spelling and grammar tools. Users can check up to 150 words for free, while registered users can check up to 300 words daily at no charge. The maker says its academic database contains over 500 million indexed texts. Integrations include a Moodle plugin, Google Docs add-on, customizable API, and Viber and Telegram bots. The maker presents it for students, educators, writers, bloggers, universities, and organizations. Paid options include a Light one-time package at $9.95, paid once and monthly packages from $27.95 a month. The maker says uploaded documents are not stored, though reports may remain in an account until deleted by the user.