Code Plagiarism Checker for CS Courses

1. Scan every submission and see exactly what matches

You suspect two students shared code, but proving it takes hours of side-by-side reading. CodeGrade's plagiarism detection does that for you. It scans every submission in the class and flags matches with a percentage similarity score. Plagiarism detection is included on every plan, including Free.

Click into any match and you get a side-by-side code comparison showing exactly which lines overlap. No guessing, no manual diffing.

Percentage similarity score for every flagged pair
Side-by-side code comparison with matched lines highlighted
Export any report to Word or PDF for academic integrity proceedings

CodeGrade plagiarism report with similarity score and matched code blocks.

CodeGrade plagiarism comparison scope: this class plus previous semesters plus external sources.

2. Compare across semesters and external sources

Students don't just copy from classmates. They copy from last semester's students, from GitHub, from solutions posted online. CodeGrade catches that too.

Link a previous CodeGrade course to compare against last semester's submissions. Upload external source files to check against public solutions. Set your similarity threshold so you only see what matters.

Compare within the class, across semesters, and against uploaded external sources
Link previous CodeGrade courses for automatic cross-semester detection
Set custom similarity thresholds to control what gets flagged

3. Supports 9 major programming languages

Plagiarism detection works across all the major programming languages your courses use, plus quiz submissions.

Whether you're teaching intro Python or advanced Java, the detection engine understands the structure of the code, not just string matching. It catches renamed variables, reordered functions, and other common obfuscation techniques.

Python, Java, JavaScript, C, C++, C#, PHP, R, Scala
Quiz submissions are also scanned
Free for courses up to 50 students. No trial, no expiration.

CodeGrade plagiarism detection language coverage using structural analysis.

Run secure assessments and protect academic integrity.

Coding exams with session lockdown, plagiarism detection across semesters, and auto-graded AI exercises. Free for up to 50 students.

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Discover how institutions use CodeGrade to improve their coding courses

Alex St. Aubin

Instructor Computer Science at the University of Nevada, Las Vegas

“CodeGrade has really made our lives easier. The lives of the TAs, the students, the teachers. It has really helped our Computer Science Department out a lot.”

Read full case study

Patrick Totzke

Full Professor

I have many students expressing how amazing it is to use CodeGrade for their submissions!

Read full case study

Angela Venable

Assistant Professor, Ivy Tech Community college

“I also find students get more engaged when they get quicker feedback.”

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Frequently Asked Questions

How does CodeGrade detect code plagiarism?

CodeGrade uses JPlag, a proven code similarity engine. It compares student submissions within the current class, across previous semesters, and against external sources to catch copied or slightly modified code. Results are shown in a side-by-side comparison report.

What programming languages does plagiarism detection support?

CodeGrade's plagiarism detection supports 9 programming languages, including Python, Java, C, C++, and JavaScript. This covers the most common languages taught in computer science courses.

Can I compare submissions across semesters?

Yes. CodeGrade can check current submissions against assignments from previous semesters, so students who reuse old solutions are flagged. You can also include external source files in the comparison.

Can I export plagiarism reports?

Yes. The side-by-side comparison reports can be exported to Word or PDF. This makes it easy to share evidence with academic integrity committees or attach documentation to a case file.

Is CodeGrade's plagiarism checker different from MOSS?

Yes. CodeGrade uses JPlag rather than MOSS. JPlag is integrated directly into the platform, so there is no need to email files to an external service or wait for results. You run the check from within CodeGrade and get the report immediately.

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The most powerful autograder

Grade code automatically across 175+ languages, with feedback that lands while students are still coding. Free for up to 50 students, forever.

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Run secure coding exams that grade themselves

IP restrictions, access passwords, and session lockdown. Students write real code in the browser. Grades are ready the moment the exam ends.

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When code needs a human eye, grade it fast

Split submissions across your team, navigate through them efficiently, and combine manual review with auto-grading.

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Catch code plagiarism before it becomes a problem

1. Scan every submission and see exactly what matches

2. Compare across semesters and external sources

3. Supports 9 major programming languages

Run secure assessments and protect academic integrity.

Discover how institutions use CodeGrade to improve their coding courses

“CodeGrade has really made our lives easier. The lives of the TAs, the students, the teachers. It has really helped our Computer Science Department out a lot.”

I have many students expressing how amazing it is to use CodeGrade for their submissions!

“I also find students get more engaged when they get quicker feedback.”

Frequently Asked Questions

How does CodeGrade detect code plagiarism?

What programming languages does plagiarism detection support?

Can I compare submissions across semesters?

Can I export plagiarism reports?

Is CodeGrade's plagiarism checker different from MOSS?

More features

Related resources

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