Copyleaks vs Crossplag: AI detector comparison
A side by side look at pricing, methodology, language support and best-fit use case. Every claim on this page is linked to a source at the bottom.
Last updated . Reviewed by IsItAI Editorial.
At a glance
Copyleaks
Israel, 2015Enterprise-grade detection with multilingual support.
- Pricing
- From $9.99/month (100 credits)
- Free tier
- Limited free credits
- API
- Yes
- Languages
- 30
Crossplag
Albania, 2017Multilingual plagiarism and AI detection for academic institutions.
- Pricing
- From $7/month
- Free tier
- Free signup with limited checks
- API
- Yes
- Languages
- 100
Side by side
| Feature | Copyleaks | Crossplag |
|---|---|---|
| Free tier | Limited free credits | Free signup with limited checks |
| Starting price | From $9.99/month (100 credits) | From $7/month |
| Cost per 1k words | $0.10 | $0.07 |
| API available | Yes | Yes |
| Languages supported | 30 | 100 |
| Founded | 2015 | 2017 |
| Country | Israel | Albania |
| Primary audience | Enterprises and institutions | Universities outside the US |
| Best for | Enterprise teams needing multilingual detection and integrations | Universities outside the US needing multilingual coverage |
| Known weakness | Pricier than competitors for low-volume users | AI detection accuracy lags peers and the primary product is plagiarism |
How each tool works
Copyleaks
Method: Proprietary classifier with paraphrasing-resistance claims. Integrates with LMS and CMS platforms.
Data handling: Enterprise tier offers no-storage option. Default plan stores submissions.
Crossplag
Method: AI detector layered onto the multilingual plagiarism engine.
Data handling: EU hosted. Submissions retained per academic-institution norms.
How accurate are AI detectors? What the research says
Two findings from independent academic research apply to almost every detector on this list, including Copyleaks and Crossplag.
1. False positives on non-native English writers. Liang et al. (Stanford, 2023) found that GPT detectors flagged over half of TOEFL essays written by non-native English speakers as AI-generated, while flagging almost none of the essays from US students. If your use case involves non-native English writers, never treat a detector verdict as proof on its own.
2. Paraphrasing reliably defeats classifiers. Sadasivan et al. (Maryland, 2023) showed that running AI output through a paraphraser drops detection performance close to chance. Both Copyleaks and Crossplag are vulnerable to this.
For a deeper breakdown of how accuracy claims hold up across 2026 testing, see our guide to how accurate AI detectors actually are in 2026.
Where Copyleaks wins
- Paraphrasing-resistance claims built into the classifier. Crossplag's AI detection is acknowledged to lag dedicated tools in accuracy.
- Native LMS and CMS integrations suit enterprise procurement workflows.
- No-storage enterprise tier available for sensitive content. Crossplag retains submissions per academic-institution norms with no documented no-storage option.
Where Crossplag wins
- Covers 100 languages versus 30. Suited to universities with large non-English student populations.
- Lower starting price at $7/month versus $9.99/month, with a lower per-1,000-word rate ($0.07 vs $0.10).
- EU hosted, which helps European universities demonstrate GDPR compliance without negotiating an enterprise tier.
Which one should you pick, Copyleaks or Crossplag?
Pick Copyleaks if you need LMS or CMS integrations, enterprise data controls, or a classifier with documented paraphrasing resistance. Pick Crossplag if you are a university outside the US needing broad multilingual coverage at a lower price point with EU hosting out of the box. Both tools are primarily plagiarism engines with AI detection added on, so treat AI scores as a supplementary signal.
Frequently asked questions
Is Copyleaks free?
Limited free credits
Is Crossplag free?
Free signup with limited checks
Can either tool be fooled by paraphrasing?
Yes. Sadasivan et al. (2023) demonstrated that paraphrasing reliably defeats most AI classifiers. Treat any detector verdict as a screening signal, not proof.
Are AI detectors fair to non-native English writers?
Independent research (Liang et al. 2023) found high false-positive rates for non-native English writing. Always combine a detector signal with other evidence, never use it as a sole basis for an academic or hiring decision.
Which one should I pick if I have to choose one, Copyleaks or Crossplag?
Pick Copyleaks if you need LMS or CMS integrations, enterprise data controls, or a classifier with documented paraphrasing resistance. Pick Crossplag if you are a university outside the US needing broad multilingual coverage at a lower price point with EU hosting out of the box. Both tools are primarily plagiarism engines with AI detection added on, so treat AI scores as a supplementary signal.
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Sources and further reading
- Copyleaks AI content detector
- Copyleaks pricing
- Crossplag AI detector (now hosted on the Crossplag app)
- Crossplag listing on G2 with pricing detail
- Liang et al. (Stanford, 2023): GPT detectors are biased against non-native English writers
- Sadasivan et al. (2023): Can AI-generated text be reliably detected?