Skip to content
SPECIFICTION
Get listed

Noplag

noplag.com

From $9.99/mo Free plan Open source WebWindowsmacOSLinuxAPISelf-hosted
Visit noplag.com
Spec score 9.2 #3 of 31 in Plagiarism Checkers

What it is

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.

Spec sheet

What it does
Noplag checks submitted text or files for plagiarism and returns similarity scores, highlighted overlaps and source links.Read 15 Oct 2026 · noplag.com
Product
Noplag is an open-source plagiarism checker with a hosted cloud service and an engine released under Apache 2.0.Read 29 Sep 2026 · noplag.com
Audience
The pricing page positions Pro for makers and small teams, Premium for agencies and publishers, and Enterprise for universities and regulated organizations.Read 29 Sep 2026 · noplag.com
API
The developer API is REST with an OpenAPI spec and webhooks, and is available on paid tiers.Read 29 Sep 2026 · noplag.com
Integrations
The features page lists Canvas, Moodle, Blackboard, and Brightspace integrations via LTI 1.3.Read 29 Sep 2026 · noplag.com
Security
Noplag says it encrypts data in transit and at rest and does not yet hold formal attestations such as SOC 2.Read 29 Sep 2026 · noplag.com
Privacy
Noplag states that submitted documents are not used to train models or shared between accounts, and EU data residency is available.Read 29 Sep 2026 · noplag.com
Compliance
The company states GDPR/UK GDPR readiness, FERPA coverage, EU data residency and WCAG 2.1 AA goals, but no SOC 2 or ISO 27001 certification yet.Read 15 Oct 2026 · noplag.com
Support
Free includes community Discord support, Pro includes email support, and Premium includes priority support with a 12-hour response target.Read 29 Sep 2026 · noplag.com
License
Noplag identifies its detection engine as open source under the Apache 2.0 license.Read 15 Oct 2026 · noplag.com
Headquarters
San Francisco, United StatesRead 28 Sep 2026 · noplag.com
Founded
2014Read 28 Sep 2026 · noplag.com
AI detection
AI-content detection is marked as coming soon and is intended to appear as a separate signal.Read 29 Sep 2026 · noplag.com
AI detection status
AI-generated-text detection is described as coming soon and will be reported separately from plagiarism scores.Read 15 Oct 2026 · noplag.com
API keys
API keys have separate live and test modes; test requests run the full pipeline without persistence, billing or quota use.Read 15 Oct 2026 · noplag.com
App-store availability
Noplag's download page marks the Apple App Store and Google Play releases as coming soon, so no store rating is stated there.Read 15 Oct 2026 · noplag.com
Check speed
Documentation says reports usually complete in 30 to 90 seconds, with longer documents taking more time.Read 15 Oct 2026 · noplag.com
Company headquarters
Noplag's own about page states that headquarters are in San Francisco with engineering teams in Ukraine, Poland and Spain.Read 15 Oct 2026 · noplag.com
Company history
Noplag says it launched in Kyiv in 2014, joined a New York EdTech accelerator in 2018 and raised $200,000 in seed funding.Read 15 Oct 2026 · noplag.com
Company legal name
The maker identifies itself as Noplag Labs, Inc.Read 15 Oct 2026 · noplag.com
Company size
LinkedIn lists Noplag Labs, Inc. as privately held with 2–10 employees.Read 15 Oct 2026 · linkedin.com
Corpus
The service compares against live web pages, Common Crawl, Wikipedia, academic sources, the Noplag Database and user folders.Read 15 Oct 2026 · noplag.com
Desktop features
The macOS desktop app supports drag-and-drop checks, watch folders, native notifications, automatic updates and OCR for scanned PDFs.Read 15 Oct 2026 · noplag.com
Developer API
Paid Pro and Premium accounts receive a REST API with OpenAPI documentation, webhooks and SDKs.Read 15 Oct 2026 · noplag.com
Document training policy
Submitted documents are stated not to be used for training AI models and not sold or shared beyond service processors.Read 15 Oct 2026 · noplag.com
Documentation
The documentation includes product help, self-hosting guides, corpus setup, fingerprint tuning, API reference, troubleshooting and a changelog.Read 15 Oct 2026 · noplag.com
Independent headquarters listing
LinkedIn lists the company headquarters and primary address in New York, which differs from the maker's current San Francisco statement.Read 15 Oct 2026 · linkedin.com
Input methods
Users can paste text, upload DOCX/PDF/TXT/ODT/RTF files or submit a URL for checking.Read 15 Oct 2026 · noplag.com
Known detection limit
The troubleshooting documentation says paraphrased or translated copying may not match and scanned PDFs without a text layer fail in the web app.Read 15 Oct 2026 · noplag.com
Languages
Detection is calibrated at launch for English, Spanish, Portuguese, Polish, and Ukrainian.Read 29 Sep 2026 · noplag.com
Limit
Noplag states that its current engine detects verbatim and near-verbatim copying and does not detect paraphrase.Read 29 Sep 2026 · noplag.com
Limit: accuracy and reliability
G2 reviews mention wrong results or missed paraphrased matches, occasional PDF errors, internet dependence and an older-looking interface.Read 15 Oct 2026 · g2.com
Limit: Capterra complaint
The sole Capterra reviewer alleged the demo did not work, recurring charges continued after cancellation and support initially ignored refund requests.Read 15 Oct 2026 · capterra.com
Limit: pricing and access
G2 reviewers repeatedly describe the product as expensive or restricted compared with alternatives and object to paying for full functionality.Read 15 Oct 2026 · g2.com
Limit: TrustRadius themes
TrustRadius reviews repeatedly call the service expensive and one review describes customer support as a weakness and the free trial as limited.Read 15 Oct 2026 · trustradius.com
Live Web search
Premium and Enterprise plans perform real-time search against current web pages instead of only an indexed corpus.Read 15 Oct 2026 · noplag.com
LMS integrations
Canvas, Moodle, Blackboard and Brightspace are supported through LTI 1.3 assignment integrations.Read 15 Oct 2026 · noplag.com
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.Read 29 Sep 2026 · noplag.com
Multilingual detection
Detection is calibrated at launch for English, Spanish, Portuguese, Polish and Ukrainian, while the interface is offered in 19 languages.Read 15 Oct 2026 · noplag.com
Notable relaunch news
A LinkedIn update says the company relaunched in 2026 with a rebuilt detection engine, new interface and corpus exceeding 150 million documents, while acknowledging unresolved issues.Read 15 Oct 2026 · linkedin.com
Paraphrase detection status
The live engine handles verbatim and near-verbatim overlap; broader paraphrase matching is listed for future MinHash and vector releases.Read 15 Oct 2026 · noplag.com
Praise: ease and detection
G2 reviewers repeatedly praise the simple interface, fast checks, detailed reports and ability to identify matching sources.Read 15 Oct 2026 · g2.com
Praise: TrustRadius themes
TrustRadius reviewers commonly praise quick scans, flexible report settings, multiple file formats, spelling and grammar checks and ease of use.Read 15 Oct 2026 · trustradius.com
Rating on Capterra
1.0 out of 5 from 1 reviewRead 15 Oct 2026 · capterra.com
Rating on G2
4.2 out of 5 from 12 reviewsRead 15 Oct 2026 · g2.com
Rating on TrustRadius
9.5 out of 10 from 9 reviews and ratingsRead 15 Oct 2026 · trustradius.com
Reports
Reports link each match to its source and show a similarity score and exact overlapping text, with PDF export.Read 29 Sep 2026 · noplag.com
Retention
Document content is purged 30 days after a free-tier check; paid users can choose a 30-, 60-, or 90-day retention window, while Enterprise can retain it without limit.Read 29 Sep 2026 · noplag.com
Retention and erasure
Default document-content retention is 30 days; dashboard deletion is targeted within 24 hours and full fingerprint purge within 30 days.Read 15 Oct 2026 · noplag.com
Security controls
Noplag states that it uses TLS 1.3 in transit, encryption at rest, least-privilege access and audit logging.Read 15 Oct 2026 · noplag.com
Self-hosting
The detection engine can be run with Docker on private infrastructure and has its own API without hosted-service keys.Read 15 Oct 2026 · noplag.com
Source-linked reports
Each detected overlap displays its source URL, similarity score and the exact matching passage, with PDF export available.Read 15 Oct 2026 · noplag.com
Sources
Its comparison sources include the open web, Common Crawl, Wikipedia, academic indexes, the Noplag Database, and users’ own folders.Read 29 Sep 2026 · noplag.com
System requirements
The desktop application is currently documented as available for macOS on Apple silicon; Windows and Linux builds are planned in that help page.Read 15 Oct 2026 · noplag.com
Uploads
Users can upload DOCX, PDF, TXT, ODT, or RTF files, paste text, or submit a URL.Read 29 Sep 2026 · noplag.com

Plans and prices

Free Free 3 checks/month · 2,500 words/check · public web + Common Crawl · Apache 2.0 self-hosting · Discord support Read 15 Oct 2026 · noplag.com
Pro $9.99 a month monthly 50 checks/month · 25,000 words/check · Noplag Database · academic index · REST API and webhooks · email support Read 15 Oct 2026 · noplag.com
Premium $19.99 a month monthly 200 checks/month · 50,000 words/check · Live Web search · branded PDF reports · priority support with 12-hour response Read 15 Oct 2026 · noplag.com
Enterprise Priced on request custom volume · all corpora and Live Web · on-prem/private cloud · SSO/SAML · Canvas, Moodle and Blackboard LMS integrations · DPA/GDPR list · SLA support Read 15 Oct 2026 · noplag.com

Every Noplag plan and price →

Strong points and limits

Strong points

  • Reports link matches to their sources
  • PDF report export
  • Supports five listed detection languages
  • REST API and webhooks on Pro

Limits

  • Does not detect paraphrase
  • Free plan allows three checks per month
  • Free checks are capped at 2,500 words
  • AI-content detection is coming soon

Who it suits

The free plan may suit occasional checks of shorter documents, while Pro is positioned for makers and small teams. The stated limits matter to anyone needing paraphrase detection or checks beyond the monthly and word caps.

Noplag in depth

Read the full write-up

Overview

Noplag is a plagiarism checker for writers, publishers, and institutions that need to trace copied passages to their sources. Its strongest case is evidence-rich reporting across web and academic collections; it is a poor fit when paraphrase detection is essential.

The service pairs a hosted workflow with an engine released under Apache 2.0. Reports link each match to its source and show the similarity score and overlapping text, with PDF export—useful for reviewing a flag rather than relying on a score alone.

Key features

Matching and reports

Noplag accepts DOCX, PDF, TXT, ODT, and RTF files, pasted text, or a URL. Its live engine uses winnowing fingerprints and live-web matching to identify verbatim and near-verbatim overlap. Checks can draw on the open web, Common Crawl, Wikipedia, academic indexes, the Noplag Database, and users’ own folders. That breadth serves source tracing, but does not turn the result into a general measure of originality: the current engine does not detect paraphrase.

Detection is calibrated for English, Spanish, Portuguese, Polish, and Ukrainian. MinHash LSH and vector reranking are future releases, not part of the current matching engine. AI-content detection is also coming soon and is intended to appear as a separate signal, so buyers who need that capability now should look elsewhere.

Workflow, privacy, and security

Canvas, Moodle, Blackboard, and Brightspace integrations are offered through LTI 1.3, while the REST API, OpenAPI spec, and webhooks support developer workflows on paid tiers. Noplag says submitted documents are not used to train models or shared between accounts, and offers EU data residency. It encrypts data in transit and at rest, but does not yet hold formal attestations such as SOC 2; organizations that require one should account for that limitation.

Retention depends on the tier: free-check document content is purged after 30 days; paid users can select 30, 60, or 90 days; Enterprise can retain content without a time limit. The Enterprise option may suit organizations with longer retention needs, while those handling sensitive material should weigh the available controls against their own compliance requirements.

Pricing

Noplag is freemium, with a free plan and a 14-day trial. Pro starts at $9.99 a month. The plans trade check volume, document size, corpus access, and support level, so the best fit depends on both workload and which sources matter.

PlanPriceWhat it includesFreefree3 checks per month, 2,500 words per check, public web and Common Crawl corpus, and community Discord support.Pro$9.99 a month50 checks per month, 25,000 words per check, Noplag Database, academic index, REST API and webhooks, and email support.Premium$19.99 a month200 checks per month, 50,000 words per check, Live Web search, branded PDF reports, and priority support with a 12-hour response target.EnterpriseCustom pricingCustom check volume, all corpora and Live Web search, on-premises or private-cloud deployment, SSO/SAML, LMS integrations, and dedicated support with an SLA.Free is enough for occasional, short checks, but its three monthly submissions and 2,500-word ceiling make it restrictive for regular editorial or academic review. Pro is positioned for makers and small teams; its larger quota, academic index, database, and API make it the practical step up for recurring work. Premium targets agencies and publishers that need higher volume, live-web search, branded reports, and faster support. Enterprise is aimed at universities and regulated organizations that need custom volume, deployment choices, identity controls, or an SLA. No seat allowance is stated for the plans, so teams should confirm account needs before choosing.

Free-tier content is purged after 30 days. Paid tiers allow a choice of 30-, 60-, or 90-day retention, while Enterprise permits unlimited retention.

Platforms

Noplag supports web, Windows, macOS, Linux, API, and self-hosted use. That mix gives individuals a browser-based option and organizations deployment and integration routes beyond the hosted service. The API is available on paid tiers; Enterprise adds on-premises or private-cloud deployment and SSO/SAML.

Who it's for

Noplag is best for writers, publishers, small teams, and institutions checking for close textual overlap and needing source-linked evidence. Its academic index and LMS integrations are relevant to education workflows, while the higher quotas and branded reports suit publishing operations. It is not the right primary check for paraphrase or AI-generated text, and the lack of formal security attestations may rule it out for organizations that require them.

Pros and cons

Inspectable evidence: Source links, similarity scores, exact overlapping text, and PDF export help reviewers assess why a match appeared.

Broad source mix: Web, Common Crawl, Wikipedia, academic indexes, the Noplag Database, and user folders cover varied comparison needs.

Useful institutional routes: LTI 1.3 integrations, paid API access, and Enterprise deployment options support larger workflows.

Clear matching boundary: No paraphrase detection, and AI-content detection is still forthcoming, limiting its value for broader integrity screening.

Tier constraints: The free plan allows only three checks monthly at 2,500 words each; regular or longer-document work requires a paid plan.

Security caveat: Encryption and EU data residency are offered, but there are no formal attestations such as SOC 2 yet.

Alternatives

PlagAware is worth comparing for a lower-priced entry point: its free tier includes 10 pages per month and up to 30 monitored URLs with a Content Protection Banner, and its Light plan costs €2.99 a month. Choose it when those page-based checks and monitored URLs suit the work better than Noplag’s source-linked checks and paid academic-index access.

PrePostSEO Plagiarism Checker is a freemium option across web, desktop, and mobile, with API access; its Basic all-in-one annual plan is $4.17 a year. Consider it when that broader platform mix or combined tool offering is more relevant than Noplag’s focused matching workflow.

Plagius is a paid option with a free trial and a 6.90 USD one-time Basic license valid for 30 days, for one Windows computer. It is a fit to consider for a short-term, single-computer Windows need; Noplag offers a wider set of platforms and institutional routes.

Copyleaks AI Detector combines AI and plagiarism detection and lists more than 30 AI-detection languages. Choose it when AI screening is a core requirement rather than a forthcoming feature.

Dolos is free, open source under MIT, and offers a web app with ZIP uploads limited to 10 MB. It is an alternative to consider when an open-source option is the priority.

PlagiarismSearch is another freemium plagiarism and AI-submission option. Compare it when that combination better matches the required workflow.

Quetext AI Detector offers a free tier with an AI detector and plagiarism checker each capped at 1,000 words, plus a summarizer and humanizer capped at 2,000 words. It is an option for readers who want those additional tools alongside short checks.

SmallSEOTools Plagiarism Checker has a free plan capped at 1,000 words per scan. Consider it for shorter free scans; Noplag’s free allowance is three monthly checks of up to 2,500 words each.

For more choices, browse Plagiarism Checkers, Plagiarism Detection Software, and AI Plagiarism Checkers.

Verdict

Noplag is a strong choice for writers, publishers, and institutions that need source-linked reports on verbatim and near-verbatim copying, especially when academic sources, APIs, or LMS workflows matter. Its transparent overlap evidence is the main reason to choose it; the inability to detect paraphrase, forthcoming AI screening, and lack of formal security attestations are the main reasons to look elsewhere.

Verdict

Noplag focuses on matching verbatim and near-verbatim text and provides source-linked reports. Its stated detection limit excludes paraphrase, so the matching scope is an important constraint.

Where Specifiction places it

Alternatives to NoplagAll alternatives →