For programming courses

Source code plagiarism detection, built for real coursework.

Overlap compares every new submission — Jupyter notebooks, Word and PDF files — against all earlier ones for the assignment, and shows you the matching code side by side.

New accounts are reviewed and approved by the administrator.

student_a.ipynb

import numpy as np

def grade(scores):

total = sum(scores)

return total / len(scores)

grade([90, 85, 77])

student_b.ipynb

import numpy as np

def compute(vals):

s = sum(vals)

return s / len(vals)

compute([90, 85, 77])

91% similar · flagged for review

Why standard text checkers miss copied code

Jupyter notebook aware

Cells are read individually — markdown, code and outputs — so two notebooks that share copied cells are flagged even when the surrounding report text differs.

Code and prose together

Compare .ipynb, .docx and .pdf submissions in one assignment. Ideal for courses where reports embed Python, R or SQL code.

Matches beyond exact copies

Similarity scoring catches renamed variables, reordered cells and lightly edited code — the usual tricks — not just identical files.

Side-by-side evidence

Open a flagged pair and see both notebooks or files next to each other, with the matching passages highlighted, ready for a conversation with the student.

Built for the way programming courses actually run

1
Create the assignment
Name it and tag it with class, semester and CRN. One assignment per task, per section.
2
Upload as they arrive
Drop in each student's notebook or document over days or weeks — every new file is checked against all earlier ones automatically.
3
Decide with evidence
Open flagged pairs side by side, with matching code and text highlighted, and make the call yourself.

Frequently asked questions

Which code file types are supported?

Jupyter notebooks (.ipynb), Word documents (.docx) and PDFs. Notebook cells — code and markdown — are extracted and compared individually.

How are Jupyter notebooks compared?

Each notebook's cells are treated as the document's content, so a student who copies a few cells from a classmate is flagged, even if their own write-up is original.

Do I have to upload everything at once?

No. Add submissions as they come in over days or weeks. Every new file is automatically checked against all earlier submissions for that assignment.

Can I tell group work apart from copying?

Similarity scores are a signal, not a verdict. Side-by-side highlighted comparisons let you judge whether shared code is expected collaboration or plagiarism.

Ready to check your next batch of notebooks?

Set up an assignment in under a minute and upload submissions as they come in.