Noplag vs Noplag Engine
Noplag
noplag.comNoplag Engine
github.comSide by side
| Figure | Noplag | Noplag Engine |
|---|---|---|
| Price from | $9.99/mo | $9.99/mo |
| Free plan | Yes | Yes |
| Free trial | Yes | Yes |
| Open source | Yes | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 4 | 4 |
| Spec score · Plagiarism Detection Software | 9.1 (#4) | 8.5 (#11) |
| API | The developer API is REST with an OpenAPI spec and webhooks, and is available on paid tiers. | The engine exposes a `/v1` API with checks, reports, uploads, progress events, and corpus management, and ships without authentication. |
| Corpus | The service compares against live web pages, Common Crawl, Wikipedia, academic sources, the Noplag Database and user folders. | The open-source engine searches a local corpus, while the hosted product additionally searches the live web. |
| Founded | 2014 | 2014 |
| Headquarters | San Francisco, United States | San Francisco, United States |
| Integrations | The features page lists Canvas, Moodle, Blackboard, and Brightspace integrations via LTI 1.3. | The Enterprise plan lists Canvas, Moodle, and Blackboard LMS integrations; the features page also names Brightspace via LTI 1.3. |
| Languages | Detection is calibrated at launch for English, Spanish, Portuguese, Polish, and Ukrainian. | The hosted product says detection is calibrated for English, Spanish, Portuguese, Polish, and Ukrainian at launch. |
| Matching | The live product uses winnowing fingerprints and live-web matching to find verbatim and near-verbatim copying; MinHash LSH and vector reranking are listed as future releases. | The engine uses winnowing fingerprints to retrieve candidate sources and a seed-and-extend aligner to locate matching character ranges. |
| Privacy | Noplag states that submitted documents are not used to train models or shared between accounts, and EU data residency is available. | The maker says submitted documents are never used to train models; hosted-plan retention is configurable and EU data residency is available on request. |
| Reports | Reports link each match to its source and show a similarity score and exact overlapping text, with PDF export. | Reports include per-source similarity, matching passage offsets, and coverage accounting. |
Plans
Noplag Engine
- FreeFree
- Pro$9.99 a month
- Premium$19.99 a month
- EnterprisePriced on request
In their own words
Noplag
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.
Noplag Engine
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.