Viper
Viper is a web app for checking documents for plagiarism and AI-generated content.
What Viper is
Viper is a web app for checking documents for plagiarism and AI-generated content. Its reports show highlighted matches, source URLs, and scores, and can be downloaded as PDFs. Viper says its checks cover 16,000+ open-access journals, 60 trillion websites and search engines, more than one million optional internal documents, and over 20 code repositories. It supports over 100 languages and cross-language matching across more than 30. Users can adjust scan sensitivity, exclude references, quotes, citations, and tables of contents, and scan up to five files in a batch. Supported formats include HTML, TXT, RTF, XML, Markdown, PDF, DOCX, PPTX, ODT, EPUB, and XLSX, among others. Google Drive uploads and Google account sign-in are available. The service runs in standard web browsers on any platform and is no longer offered as downloadable software. Its free service permits one scan of up to 5,000 words per document. Viper is designed for students and also serves institutions, schools, universities, businesses, and professionals.
Good
- Checks for plagiarism and AI-generated content
- Reports include highlighted matches and source URLs
- Supports over 100 languages
- Can scan up to five files at once
- Accepts uploads from Google Drive
Watch out
- Free use is limited to one scan per document
- Free scan limit is 5,000 words per document
- No longer available as downloadable software
- Paid credits are one-time purchases
Who it suits
Viper may suit students checking documents, as well as institutions, schools, universities, businesses, and professionals. Its browser-based access and broad file-format support may fit users working across different platforms.
Verdict
Viper combines plagiarism and AI-content checks with adjustable scan settings and downloadable PDF reports. Check the one-scan free limit and credit-based paid options against the size and frequency of your document checks.
Plans and prices
From Viper's own pricing page, checked 4 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Small | £5, paid once | 10 credits · up to 250 words per credit · £5.00 for 10 credits |
| Starter | £9, paid once | 20 credits · up to 250 words per credit · £9.00 for 20 credits |
| Standard | £14.95, paid once | 50 credits · up to 250 words per credit · £14.95 for 50 credits |
| Professional | £25.95, paid once | 100 credits · up to 250 words per credit · £25.95 for 100 credits |
| Advanced | £34.95, paid once | 200 credits · up to 250 words per credit · £34.95 for 200 credits |
| Premium | £69.95, paid once | 500 credits · up to 250 words per credit · £69.95 for 500 credits |
| Ultimate | £119.95, paid once | 1000 credits · up to 250 words per credit · £119.95 for 1000 credits |
The facts
Each one read from Viper's own pages, with the date it was checked.
What it does
- Confidentiality
- Viper says repository storage is optional and stored documents are not shared publicly; users can request permanent deletion through support.checked 4 Oct 2026
- File formats
- Viper lists support for formats including HTML, TXT, RTF, XML, Markdown, PDF, DOCX, PPTX, ODT, EPUB, XLSX and more.checked 4 Oct 2026
- Integration
- Viper lets users upload documents from Google Drive and supports signing in with a Google account.checked 4 Oct 2026
- Intended users
- Viper says it is designed for students and also serves institutions, schools, universities, businesses and professionals.checked 4 Oct 2026
- Language support
- Viper says it supports over 100 languages and cross-language matching across more than 30 languages.checked 4 Oct 2026
- Payment security
- Viper says payment providers process card details directly and the site does not store them.checked 4 Oct 2026
- Purpose
- Viper checks documents for plagiarism and AI-generated content.checked 4 Oct 2026
- Reports
- Viper provides reports with highlighted matches, source URLs and scores, and downloadable PDF reports.checked 4 Oct 2026
- Scan controls
- Users can adjust scan sensitivity, exclude references, quotes, citations and tables of contents, and bulk scan up to five files at once.checked 4 Oct 2026
- Sources
- Viper says it checks against 16,000+ open-access journals, 60 trillion websites and search engines, 1M+ optional internal documents, and 20+ code repositories.checked 4 Oct 2026
- Support
- Viper offers support through LiveChat and email for paid scans.checked 4 Oct 2026
Money
- Free scan limit
- The terms state that the free service is limited to one scan of up to 5,000 words per document.checked 4 Oct 2026
The company
- Headquarters
- Fujairah, United Arab Emirateschecked 28 Sep 2026
Where it runs
- Platform availability
- Viper is an online app accessible through standard web browsers on any platform and is no longer available as downloadable software.checked 4 Oct 2026
Alternatives to Viper
- 1
Noplag
Free planOpen sourceWebAPILinuxmacOS8.3From $9.99 a month - 2
Plagiarisma
Free planAndroidWebAPIExtension8.0From $99 a year - 3
Dolos
Free planOpen sourceWebAPILinuxmacOS7.7Free plan - 4
Originality.ai
Free planWebAPIExtension7.6From $12.95 a month - 5
Copyscape
Free planWebAPISelf-hosted7.5From $4.95 a month - 6
PlagAware
Free planWebAPI7.4Free plan