Detect Code Plagiarism Beyond Copy-Paste
CodeSimilar uses Abstract Syntax Tree analysis to catch structurally similar code even when variable names, formatting, and comments have been changed. Built for CS instructors and bootcamp teachers.
How It Works
Upload Assignments
Drag and drop student code files. Supports Python, JavaScript, Java, C++, and more.
AST Analysis
Our engine parses each file into an Abstract Syntax Tree and compares structural patterns across all submissions.
Review Reports
Get a ranked similarity matrix with highlighted code sections and confidence scores for each pair.
Simple Pricing
One plan. Everything included. No surprises.
Cancel anytime
- ✓Unlimited submissions
- ✓AST-based similarity detection
- ✓Multi-language support
- ✓Downloadable PDF reports
- ✓Student submission dashboard
- ✓Email support
Frequently Asked Questions
How is AST analysis different from text-based plagiarism detection?
Text-based tools catch direct copy-paste. AST analysis parses code into its structural tree, so renaming variables, changing formatting, or reordering statements won't fool it. We compare the logical structure, not the surface text.
Which programming languages are supported?
CodeSimilar currently supports Python, JavaScript, TypeScript, Java, C, and C++. More languages are added regularly based on instructor demand.
Is my students' code kept private?
Yes. All uploaded files are encrypted at rest and in transit. Code is never shared, sold, or used for training. You can delete all submissions at any time from your dashboard.