Noplag Engine
Noplag Engine: A configurable, self-hosted matcher for teams that need auditable similarity reports. Ranked #26 of 28 in Plagiarism Detection Software by our editors (6.5/10); pricing: Free plan · 14-day trial; best for teams self-hosting configurable text matching.
At a glance
- Editor score6.5 / 10
- PricingFree plan · 14-day trial
- Best forTeams self-hosting configurable text matching
- Free planYes
- Paid fromFree
- AI detectionNo
- Founded2014 · San Francisco, United States
- Facts checked21 Sep 2026
Where it wins
- Apache 2.0 engine supports Docker-based self-hosting
- Character-level alignment shows matched passages and source references
- REST API, webhooks, and LMS integrations support operational workflows
Where it doesn't
- Does not include standalone AI-writing detection
- Paraphrase and translated-plagiarism detection are not shipped
- Configuration and infrastructure management require technical ownership
Our verdict on Noplag Engine
Noplag Engine is an Apache-2.0 open-source plagiarism detection engine for developers, organizations, educators, and publishers that need control over text-matching infrastructure. It processes documents into winnowing fingerprints, retrieves candidate sources through fingerprint overlap, and refines matches to character-level ranges. Similarity reports include matched passages and source references, while the engine can run on an organization’s own infrastructure through Docker or connect through its REST API and OpenAPI documentation.
The plan structure covers different checking and deployment needs. Free includes 3 checks per month, 2,500 words per check, the public web and Common Crawl corpus, and self-hosting with the Apache 2.0 engine. Pro adds 50 checks per month, 25,000 words per check, the Noplag Database, the Academic index, REST API access, and webhooks. Premium lists 200 checks per month, 50,000 words per check, Live Web search, branded PDF reports, and priority support. Enterprise adds custom check volume, on-premises or private-cloud deployment, SSO/SAML provisioning, and LMS integrations. A 14-day free trial is also available.
Its strongest fit is for teams that value configurable corpora, auditable matching, and integration flexibility over a packaged AI-detection suite. Canvas, Moodle, Blackboard, and Brightspace integrations extend its reach into education workflows, while webhooks and the API support custom applications. The matching approach is focused: it covers direct and near-verbatim copying with source retrieval and detailed alignment, but does not ship standalone AI-writing detection, paraphrase detection, or translated-plagiarism detection. Choose Noplag Engine when self-hosting and operator-controlled infrastructure matter; choose an alternative when broader semantic or AI-focused detection is central.
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Noplag Engine pricing
All 4 Noplag Engine plans and prices →
Noplag Engine fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| AI detection | No |
| LMS integrations | Yes |
| API access | Yes |
| Browser extension | Not verified |
| Supported languages | Not verified |
| Maximum check size | 25000 words/check |
| Free trial | 14 days · no card needed |
| Deployment | Self-hosted |
| Support | Community, Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 7 integrations: REST API, OpenAPI, Webhooks, Canvas, Moodle, Blackboard … |
| Pricing | Free plan · 14-day trial (source) |
| Website | github.com |
| Facts checked | 21 Sep 2026 |
Noplag Engine integrations
Noplag Engine lists 7 integrations on its own site.
- REST API
- OpenAPI
- Webhooks
- Canvas
- Moodle
- Blackboard
- Brightspace
Alternatives to Noplag Engine
- Turnitin SimilarityA comprehensive academic similarity checker with LMS workflows and advanced match flags.9.3
- DrillBitBroad academic and classroom checks with one-time page-credit pricing.9.1
- iThenticateA scholarly similarity checker with deep academic coverage and flexible organizational integrations.8.9
See all Noplag Engine alternatives →
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Noplag Engine is listed in our Plagiarism Detection Software directory. Add the badge to your site — it links back to this page.
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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