Copyleaks AI Detector vs Noplag
Copyleaks AI Detector
copyleaks.com
Noplag
noplag.comSide by side
| Figure | Copyleaks AI Detector | Noplag |
|---|---|---|
| Price from | $13.99/mo | $9.99/mo |
| Free plan | — | Yes |
| Free trial | Yes | Yes |
| Open source | — | Yes |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| Linux | — | Yes |
| API | Yes | Yes |
| Self-hosted | Yes | Yes |
| Plans published | 12 | 4 |
| Spec score · Plagiarism Checkers | 9.2 (#1) | 9.2 (#3) |
| Spec score · Plagiarism Detection Software | 9.2 (#1) | 9.1 (#4) |
| Spec score · AI Plagiarism Checkers | 9.2 (#1) | 9.2 (#3) |
| API | The developer product is a REST API returning section-level human or AI classifications, an overall summary and explanations. | The developer API is REST with an OpenAPI spec and webhooks, and is available on paid tiers. |
| Compliance | The company lists SOC 2, SOC 3, GDPR, PCI DSS and NIST Risk Management Framework alignment. | 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. |
| Headquarters | New York, NY, United States | San Francisco, United States |
| LMS integrations | Official integrations include Canvas, D2L Brightspace, Moodle, Blackboard, Schoology, Edsby and Sakai. | Canvas, Moodle, Blackboard and Brightspace are supported through LTI 1.3 assignment integrations. |
| Rating on Capterra | 4.4 out of 5 from 91 reviews | 1.0 out of 5 from 1 review |
| Rating on G2 | 4.5 out of 5 from 41 reviews | 4.2 out of 5 from 12 reviews |
| Rating on TrustRadius | 8.8 out of 10 from 21 reviews | 9.5 out of 10 from 9 reviews and ratings |
| Security | Copyleaks states that data is encrypted at rest with AES-256 and that it holds SOC 2 and SOC 3 certifications and supports GDPR compliance. | Noplag says it encrypts data in transit and at rest and does not yet hold formal attestations such as SOC 2. |
| Self-hosting | Security documentation describes on-premises Cloud Private Hubs for organizations retaining data in their own environment. | The detection engine can be run with Docker on private infrastructure and has its own API without hosted-service keys. |
| What it does | Copyleaks analyzes text for AI generation, plagiarism, paraphrasing and content authenticity. | Noplag checks submitted text or files for plagiarism and returns similarity scores, highlighted overlaps and source links. |
Plans
Copyleaks AI Detector
- PersonalPriced on request
- ProPriced on request
- Personal$16.99 a month
- Personal (monthly billing)$16.99 a month
- Pro$99.99 a month
- Pro (monthly billing)$99.99 a month
- Personal (annual billing)$167.88 a year
- Pro (annual billing)$899.88 a year
- EducationPriced on request
- EducationPriced on request
In their own words
Copyleaks AI Detector
Copyleaks AI Detector identifies AI-written text, including writing that mixes AI and human passages. It supports more than 30 languages and names GPT-5, GPT-4, ChatGPT, Claude, Gemini, DeepSeek, Llama, Bloom, Rytr, and Jasper among the sources it detects. AI Logic explains flagged results, displays AI phrase frequency, and can identify text appearing in published content elsewhere. The web detector scans up to 25,000 characters without login; the website platform requires at least 255 characters and accepts up to 2,000 pages. A Chrome and Edge extension accepts 350 to 25,000 characters, and a Google Docs add-on and education LMS integrations connect it to other workflows. Personal costs $13.99 a year with annual billing or $16.99 a month; Pro costs $74.99 a year with annual billing or $99.99 a month. A free plan and free trial are listed. Copyleaks says data is encrypted at rest with AES-256, reports SOC 2 and SOC 3 certifications, and supports GDPR compliance.
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.