Noplag Engine vs Plagium

Noplag Engine is an open-source plagiarism detection tool that checks text for verbatim and near-verbatim matches against a corpus you control. It uses winnowing fingerprints to find candidate sources, then aligns matching character ranges. Reports show similarity by source, passage offsets, and coverage accounting. It accepts.txt,.md,.pdf, and.docx files, with folder ingestion and HTTP uploads, and exposes a /v1 API for checks, reports, uploads, progress events, and corpus management. The API ships without authentication. The open-source engine searches a local corpus; the hosted product also searches the live web. It does not detect paraphrase, semantic similarity, or AI-written text. The engine can run on your own hardware with Docker Compose under the Apache 2.0 license. The repository lists Python 3.12 or newer for development and PostgreSQL in its Docker Compose setup. The free hosted plan costs nothing and allows 3 checks per month, while self-hosting permits unlimited local checks. Pro costs $9.99 a month and Premium costs $19.99 a month; Enterprise pricing is custom.

Plagium analyzes text for similarity with other material and offers a separate tool for identifying patterns compatible with AI-generated writing. Its plagiarism service compares submitted text with an online database and reports similarities with links to original sources. The AI Detector uses statistical and probabilistic analysis of writing patterns. Deep Search accepts Microsoft Word, PDF, and native text files; Google Drive integration and a Google Docs add-on support document analysis. Institutional users can access an API, while business solutions can integrate with corporate CRM, ERP, and document-management systems. Plagium presents solutions for educational institutions, publishers, editors, companies, researchers, and compliance teams. The free account costs nothing and allows five daily searches with a 4,000-character limit, but excludes Deep Search and API access. Plagium says submitted content remains owned by the user and is processed for analysis, report generation, and service improvement. Reports are automated estimates rather than definitive proof, and private, unpublished, or non-indexed material may not be detected.