Updated November 2025

Codequiry vs Dolos vs MOSS vs JPlag

An in-depth comparison of four leading code plagiarism detection tools. Compare features, capabilities, and pricing to find the right solution for your needs.

Quick comparison

Four leading tools, each optimized for different needs—from AI-powered enterprise detection to lightweight peer comparison.

Best overall

Codequiry

AI detection, GitHub scanning, 51+ languages

Best free

MOSS

Classic tool, basic similarity, no modern features

Best research

JPlag

Open source, academic focus, self-hosted

Best visual

Dolos

Modern UI, great graphs, small cohorts

Feature comparison

Side-by-side capabilities analysis across detection methods, language support, and platform integrations.

Codequiry
MOSS
JPlag
Dolos
AI code detection
ChatGPT, Copilot, Claude
Web & GitHub scanning
40B+ sources
Language support
51+
~15
<10
<10
Peer comparison
With clustering
API & integrations
API + LMS plugins
CLI only
CLI only
CLI only
Report quality
Side-by-side + evidence
Basic listing
Visual scores
Graph viz
Pricing
Paid plans
Free
Free (OSS)
Free (OSS)

Key insight

Codequiry is the only tool with comprehensive web scanning and AI code detection—critical for catching modern plagiarism methods. Free tools excel at basic peer comparison but miss external sources entirely.

In-depth analysis

Detailed breakdown of capabilities, strengths, limitations, and ideal use cases for each platform.

Codequiry

Enterprise-grade platform with AI detection and web scanning

AI code detection

Identifies ChatGPT, Copilot, Claude-generated code

Web & GitHub scanning

40B+ sources including Stack Overflow, Chegg

51+ languages

Python, Java, C++, JS, TS, Go, Rust, Swift, more

API & integrations

RESTful API, CLI, bulk upload, webhook support

Strengths

  • Only tool with AI code detection
  • Comprehensive web & GitHub scanning
  • Side-by-side diffs with evidence links
  • Enterprise security & compliance
  • Scales to thousands of students

Considerations

  • Paid service (not free)
  • May be overkill for small courses under 30 students
Best for: Universities, coding bootcamps, enterprises needing AI detection and web scanning

MOSS

Classic free tool for basic peer-to-peer comparison

Strengths

  • Free for academic use
  • 30+ years of proven reliability
  • No installation needed
  • Widely recognized in academia

Limitations

  • No web or GitHub scanning
  • No AI code detection
  • Command-line only interface
  • Basic HTML reports
  • No API access
  • Email registration required
Best for: Small courses with limited budgets, basic peer comparison only

JPlag

Open-source tool for academic research and small courses

Strengths

  • Open source and customizable
  • Free to use
  • Self-hosted (full data control)
  • Active GitHub development
  • Visual HTML reports

Limitations

  • Fewer than 10 languages
  • No web or GitHub scanning
  • No AI code detection
  • Requires Java setup
  • No cloud option
  • Manual file management
Best for: Academic research, small courses, institutions requiring on-premise hosting

Dolos

Modern visualization tool for small cohorts

Strengths

  • Beautiful modern UI
  • Excellent visual similarity graphs
  • Interactive reports
  • Open source
  • Good for teaching concepts

Limitations

  • Fewer than 10 languages
  • No web or GitHub scanning
  • No AI code detection
  • Requires Docker setup
  • Best for small cohorts only
  • Limited documentation
Best for: Small research groups under 100 students, visual similarity analysis

Which tool for your needs

Recommendations based on institution size, budget, and feature requirements.

Large universities

500+ students, AI detection needed

Codequiry

Web scanning, AI detection, enterprise scale, bulk file upload

Small courses

Under 50 students, tight budget

MOSS JPlag

Free, basic peer comparison, minimal setup

Coding bootcamps

100-300 students, remote learning

Codequiry

Cloud-based, detects GitHub copying, API integration

Enterprise hiring

Technical assessments, candidate screening

Codequiry

Legal-grade evidence, security compliance, API access

Academic research

Algorithm studies, experimentation

JPlag Dolos

Open source, customizable, visual analysis tools

Budget conscious

Limited funding, basic detection

MOSS

Free, proven track record, widely documented

Pricing

Understanding costs and total cost of ownership across all platforms.

Codequiry

Paid

Subscription-based

  • Cloud-hosted, no IT overhead
  • 24/7 support & auto-updates
  • All features included
  • Education discounts available

MOSS

Free

Academic use only

  • No subscription cost
  • Time cost for manual setup
  • No support or guarantees
  • Stanford queue wait times

JPlag

Free

Open source

  • No subscription cost
  • Self-hosting expenses
  • Java setup & maintenance
  • No official support

Dolos

Free

Open source

  • No subscription cost
  • Docker setup required
  • Self-hosting expenses
  • Limited community support

Total cost of ownership

Free tools require IT staff time for setup and maintenance, miss AI-generated and web-sourced plagiarism, require manual workflows, and may create institutional risk. For large institutions, comprehensive paid solutions often have lower total cost when accounting for these hidden factors.

Frequently asked questions

Common questions about choosing and implementing code plagiarism detection tools.

The main differences are: (1) Web Scanning — Codequiry scans 40B+ web sources and GitHub repositories while MOSS only compares files you submit. (2) AI Detection — Codequiry detects AI-generated code from ChatGPT, Copilot, and Claude while MOSS cannot. (3) Reporting — Codequiry provides side-by-side diffs with source links and evidence, while MOSS shows basic match listings. (4) Integration — Codequiry offers modern API/CLI/bulk import and LMS plugins, while MOSS uses older CLI submission only.

Codequiry is the only tool among these four that specifically detects AI-generated code from sources like ChatGPT, GitHub Copilot, Claude, and other AI assistants. This is achieved through machine learning models trained on millions of code samples to identify characteristic patterns of AI-generated code. Dolos, JPlag, and MOSS were not designed for this and cannot reliably detect AI-generated code.

Yes, for comprehensive code integrity in universities, Codequiry offers significant advantages:
  • Web and GitHub scanning (JPlag doesn't have this)
  • AI-generated code detection (JPlag doesn't have this)
  • 51+ programming languages (JPlag supports fewer than 10)
  • Cloud-based scalability (JPlag requires self-hosting)
  • Side-by-side diff reports with evidence links (JPlag has basic reports)
  • Bulk file upload and API access (JPlag requires manual workflow)
That said, JPlag is excellent for basic peer-to-peer similarity checking in research settings or small courses with limited budgets.

Dolos is a research-focused tool with excellent visualization but has limitations compared to Codequiry:
  • Dolos supports fewer than 10 languages vs Codequiry's 51+
  • Dolos doesn't scan web/GitHub sources
  • Dolos lacks AI-generated code detection
  • Dolos requires local installation while Codequiry is cloud-based
  • Dolos is best for small cohorts (under 100) while Codequiry scales to thousands
  • Codequiry offers more comprehensive reporting with side-by-side diffs and source attribution
Choose Dolos if you prioritize visual similarity graphs for small research groups. Choose Codequiry for production use in large courses or institutions.

No, MOSS cannot detect code copied from GitHub or any external web sources. MOSS only compares the source files you submit to it against each other. It has no capability to search the web, scan GitHub repositories, or check Stack Overflow. In contrast, Codequiry automatically scans GitHub repositories and 40 billion+ web sources to detect copied code from online sources. This is one of the most significant limitations of MOSS in today's environment where GitHub and online code repositories are prevalent.

Codequiry supports the most programming languages with 51+ languages including Python, Java, C, C++, C#, JavaScript, TypeScript, PHP, Ruby, Go, Rust, Swift, Kotlin, Scala, Haskell, R, MATLAB, and many more. In comparison, Dolos and JPlag support fewer than 10 languages each, while MOSS supports multiple languages but fewer than Codequiry. This extensive language support makes Codequiry suitable for diverse computer science curricula and enterprise environments with polyglot codebases.

Pricing varies significantly:
  • MOSS: Free for academic use but requires manual setup and has very limited features (no web scanning, no AI detection)
  • Dolos & JPlag: Open-source and free but require local installation, IT maintenance, and lack enterprise features
  • Codequiry: Paid subscription service with plans starting for educators and scaling to enterprise level
While the free tools have no subscription cost, consider the total cost of ownership including: IT staff time for setup/maintenance, opportunity cost of undetected plagiarism (especially from web sources and AI), time spent on manual processes, and potential institutional reputation risk. For larger institutions, Codequiry's comprehensive features often result in lower TCO.

Codequiry uses multi-layer detection combining structural analysis, fingerprinting, AI heuristics, and web scanning, providing higher accuracy for real-world scenarios. MOSS and JPlag use token-based and similarity heuristics respectively, which work well for peer-to-peer comparison but miss external sources and AI-generated code. Codequiry's detection includes: variable renaming, code reordering, structural changes, comment stripping, formatting changes, and advanced obfuscation techniques. Additionally, Codequiry's web scanning catches plagiarism that MOSS/JPlag cannot detect at all (external sources), making it significantly more comprehensive for overall plagiarism detection in modern educational environments.

You only need one tool — choose based on your requirements. Most institutions use either Codequiry (for comprehensive detection including web/AI sources) or MOSS/JPlag/Dolos (for basic peer-to-peer comparison). Using multiple tools simultaneously is unnecessary and creates workflow complexity. Some research projects may use Codequiry for production plagiarism detection while using JPlag or Dolos for academic research on detection algorithms. For 95% of use cases, choose the single tool that best matches your needs and budget.

Codequiry supports bulk file upload through our zip file importer. You can download all student submissions from Canvas, Moodle, Blackboard, or any LMS as a zip file, then upload it to Codequiry for analysis—no file size limits. MOSS, JPlag, and Dolos require manual file handling and typically have more complex upload processes. Codequiry's drag-and-drop bulk importer makes it efficient to handle large classes.

The bottom line

Modern plagiarism detection requires web scanning and AI detection capabilities. Free tools (MOSS, JPlag, Dolos) excel at basic peer comparison but miss external sources and AI-generated code entirely. Codequiry is purpose-built for today's challenges: detecting code from GitHub, Stack Overflow, ChatGPT, and Copilot with comprehensive evidence and enterprise integrations.

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