Code plagiarism checker
Codequiry checks source code three ways at once: against the rest of the class, against GitHub, Stack Overflow and the web, and for code written by AI. Every flag comes with the matching lines side by side, so you can see exactly why.
2-day free trial. Checks every file against classmates, the web and AI, in 65+ languages.
| Submission | Peer | Web | AI | Why it stands out |
|---|---|---|---|---|
| Student 14 | 12% | 96% | 7% | Copied from GitHub, names changed |
| Student 03 | 88% | 4% | 11% | Matches Student 27 line for line |
| Student 27 | 88% | 6% | 9% | Matches Student 03 line for line |
| Student 09 | 9% | 3% | 91% | Likely AI-written, reasons listed |
| Student 21 | 6% | 2% | 5% | Nothing to review |
Every submission gets three scores. The few worth a closer look rise to the top, and each score opens the lines behind it.
Used in programming courses at
Three checks in one
Most copied code comes from one of three places. A peer-only tool like MOSS sees the first. Codequiry checks all three in the same run.
Classmates and past terms
Every submission against every other, and against earlier terms of the course. Structure is compared, so renaming and reformatting do not hide a copy.
GitHub, Stack Overflow and the web
Each file is searched against GitHub, Gists, Stack Overflow, Software Heritage and the indexed web, with a link to the source it matched.
AI-written code
A detector trained on ChatGPT, Claude, Gemini and Copilot output gives each file a probability and the reasons behind it. More on AI detection.
65+ languages
Python, Java, C and C++ to Go, Rust, SQL and Jupyter notebooks, including solutions translated from one language to another.
What you see
A score on its own proves nothing. What makes a case is being able to point at the lines, so every result opens the evidence behind it.
- Side-by-side matches for classmates and web sources, with the shared lines marked and a link to the original.
- AI findings with reasons, so you can weigh them rather than take a number on trust.
- Starter code left out and common boilerplate labeled, so they do not bury real copying.
- Reports you can export and share if a case goes further.
How it works
- Upload the submissions as a ZIP, one folder or file per student, or pull them from your LMS.
- Pick the checks. Peer comparison, web sources and AI detection can run together or on their own.
- Get the results in minutes for a typical class, sorted so the highest scores are first.
- Review and decide. Open each flag, read the lines, and talk to the student. The checker finds; a person decides.
Want the detail behind the scores? Code plagiarism: what it is and how to detect it explains tokenizing, fingerprinting and why renaming does not work, and how to detect code plagiarism walks through a case step by step.
Check your next assignment
Upload the class as a ZIP and see all three checks on every file.
2-day free trial
Where it fits
- In your LMS. Canvas over LTI 1.3, plus Moodle, Blackboard, Brightspace and more.
- In your tools. A REST API with SDKs, a command-line client, a desktop app, and an MCP server for Claude and Cursor.
- While students write. Window is a student IDE that records pastes as they happen, for assignments where the process matters too.
What instructors say
“The rise of AI-generated code has made verifying student mastery a critical challenge. Codequiry is now essential for upholding our academic standards and ensuring every submission represents original effort.”
“We found a 99% match between a student and a Chegg solution. I can't believe CS departments are missing this.”
Pricing
- Free check: compares up to 20 submissions with each other, with no account.
- Single check, $50: one assignment against classmates, the web and AI, with no account.
- Plans: for courses and departments, starting with a 2-day free trial.
Frequently asked questions
What is a code plagiarism checker?
A tool that compares source code to find work copied from classmates, the web or AI. It reads program structure rather than text, so renamed variables, new comments and reformatting do not hide a copy.
What does Codequiry check code against?
The other submissions in the assignment, earlier terms of the course, GitHub, GitHub Gists, Stack Overflow, Software Heritage and the indexed web. An AI detector also checks each file for code written by ChatGPT, Claude, Gemini or Copilot.
How accurate is it?
Each score comes with the matched lines side by side, so you can see what drives it. A high score is a signal to look closer, not a verdict: short programs and common algorithms can match between honest students, which is why a person makes the call.
Which programming languages are supported?
More than 65, including Python, Java, C, C++, C#, JavaScript, TypeScript, Go, Rust, Kotlin, Swift, PHP, Ruby, R, MATLAB, SQL and Jupyter notebooks.
How long does a check take?
Minutes for a typical class. Larger batches and web checks take longer, and you can leave the page while it runs.
Can I automate checks?
Yes. There is a REST API with SDKs, a command-line client, and an MCP server for AI assistants, and Codequiry connects to Canvas, Moodle, Blackboard and other LMSs.
Is there a free version?
Yes. The free check compares up to 20 submissions with each other, with no account. Web and AI checks come with a paid plan, a free trial, or a single $50 check.
Find out what's in your next assignment
Every submission checked against classmates, the web and AI, with the lines side by side.
Start free trial2-day free trial
Just one assignment? Run a single check