Noplag vs Quetext AI Detector

Noplag is an open-source plagiarism checker with a hosted cloud service and an engine released under Apache 2.0. Its current matching uses winnowing fingerprints and live-web comparison to find verbatim and near-verbatim copying; it does not detect paraphrase. Sources include the open web, Common Crawl, Wikipedia, academic indexes, the Noplag Database and users’ own folders. Submit DOCX, PDF, TXT, ODT or RTF files, paste text or provide a URL. Reports link matches to their sources, display similarity scores and exact overlapping text, and can be exported as PDFs. Detection is calibrated at launch for English, Spanish, Portuguese, Polish and Ukrainian. AI-content detection is marked as coming soon and intended as a separate signal. The free plan allows three checks per month, up to 2,500 words per check, with community Discord support. Pro costs $9.99 a month and includes 50 monthly checks, up to 25,000 words per check, database and academic-index matching, REST API and webhooks, and email support. A 14-day trial is listed.

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.