IsItAI 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
IsItAI
UK, 2024UK-built AI detection that gives you a confidence score, not a verdict.
- Pricing
- From £4.99/month
- Free tier
- 5 scans/day free
- 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 | IsItAI | Crossplag |
|---|---|---|
| Free tier | 5 scans/day free | Free signup with limited checks |
| Starting price | From £4.99/month | From $7/month |
| Cost per 1k words | £0.05 (Pro plan equivalent) | $0.07 |
| API available | Yes | Yes |
| Languages supported | 30 | 100 |
| Founded | 2024 | 2017 |
| Country | UK | Albania |
| Primary audience | Educators, recruiters and content teams | Universities outside the US |
| Best for | Teachers, students and recruiters who want a clear confidence score and source-passage highlighting | Universities outside the US needing multilingual coverage |
| Known weakness | Smaller brand than US incumbents | AI detection accuracy lags peers and the primary product is plagiarism |
How each tool works
IsItAI
Method: Multi-model ensemble. Combines several open detectors and weights agreement. Returns a confidence band rather than a binary verdict.
Data handling: GDPR compliant. UK and EU hosted. Submitted text is not stored after the scan completes.
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 IsItAI 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 IsItAI 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 IsItAI wins
- AI detection is the core product, with passage-level highlighting and a confidence band. Crossplag layers AI detection onto a plagiarism engine and its AI accuracy lags peers.
- Returns a confidence band and flagged source passages rather than a single number.
- No-storage GDPR policy: submitted text is not retained after the scan.
Where Crossplag wins
- Very wide language coverage at 100 languages versus 30, useful for non-English institutions.
- Bundles plagiarism and AI detection for universities that need both in one tool.
- EU hosted, with retention aligned to academic-institution norms.
Which one should you pick, IsItAI or Crossplag?
Pick IsItAI if AI detection quality and explainable flagged passages matter most and you want a no-storage tool. Pick Crossplag if you are a non-US university needing very broad multilingual plagiarism plus AI detection in one product. Note that Crossplag's AI accuracy lags its plagiarism core, so weight its AI flags carefully.
Frequently asked questions
Is IsItAI free?
5 scans/day free
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, IsItAI or Crossplag?
Pick IsItAI if AI detection quality and explainable flagged passages matter most and you want a no-storage tool. Pick Crossplag if you are a non-US university needing very broad multilingual plagiarism plus AI detection in one product. Note that Crossplag's AI accuracy lags its plagiarism core, so weight its AI flags carefully.
Try IsItAI free
5 free scans a day. No credit card. UK hosted and GDPR compliant.
Sources and further reading
- IsItAI homepage
- Pricing
- How it works
- 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?