The programming plagiarism checker for source code.
Codequiry is a code plagiarism checker built for programming assignments. Run a full plagiarism check across MOSS, JPlag, Dolos, AI detection, and web sources in 65+ languages, with an evidence-rich report on the other side. Built for educators and institutions.
Peer similarity
Find clusters of similar submissions even after cosmetic changes like renaming, reordering, or comment edits.
Web source matching
Compare across billions of sources, repositories, and blocked sites to detect copy‑paste from the internet.
Weighted evidence
Reduce false positives with a scoring model that prioritizes structural and logical similarity over superficial edits.
AI indicators
Detect generated‑code patterns and mixed authorship risk with explainable signals.
Explainable reports
Side‑by‑side diffs, source links, and similarity clusters organized for quick review.
Programming plagiarism checker FAQ
What is a programming plagiarism checker?
A programming plagiarism checker analyzes source code, rather than prose, to find copied, shared, or AI-generated code. Codequiry compares each submission to your peer group and to web sources including GitHub and Stack Overflow, understands code structure in 65+ programming languages, and returns weighted similarity scores with side-by-side evidence.
Which programming languages does the code plagiarism checker support?
Codequiry supports 65+ programming languages including Python, Java, C++, C#, JavaScript, TypeScript, Go, Rust, Ruby, PHP, Swift, and Kotlin, with no per-language configuration. It detects similarity even after variable renaming, reordering, and comment changes.
Can this programming plagiarism checker detect AI-generated code?
Yes. Alongside peer and web plagiarism detection, Codequiry includes a built-in AI code detector that flags code generated by ChatGPT, GitHub Copilot, Claude, and Gemini, so a single report covers both copied and AI-written code.
Is there a free way to check code for plagiarism?
You can create a Codequiry account and run your first source code plagiarism check for free. Paid plans add MOSS, JPlag, Dolos, larger web-source coverage, API and CLI access, and higher submission volumes for courses and engineering teams.
Check code for plagiarism in minutes
Get started, then invite your team or class when you are ready.
Get Started FreeTools and sources referenced on this page
Codequiry is compared with these tools above. Each link goes to the project's official site so you can check the claims yourself.
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MOSS (Measure of Software Similarity)
Stanford University, Alex Aiken
Free academic similarity service from 1994 that fingerprints code with winnowing and reports matching passages between submissions.
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JPlag
Karlsruhe Institute of Technology, open source
Open-source token-based detector that compares programs with Greedy String Tiling and produces a similarity report per pair.
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Dolos
Ghent University, open source
Open-source similarity tool built on tree-sitter parsing, with a web interface for exploring clusters of related submissions.
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