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While there isn’t a single “standard” plagiarism checker built into Visual Studio Code (VS Code), you can use several extensions and external tools that integrate with it to verify code originality.
VS Code Extensions
The following extensions can be installed directly from the VS Code Marketplace:
- AntiPlagiarism: Specifically designed to find code duplication within methods. It allows you to compare your source code against itself or a provided reference solution, which is useful for refactoring or checking against a “master” version.
- Copyleaks: While primarily known as an online tool, Copyleaks offers AI-powered code plagiarism detection for over 100 programming languages. It can identify exact matches, similarities, and even paraphrased code.
- Codequiry: Although it’s often used via its web platform, Codequiry provides a CLI (Command Line Interface) and API that can be integrated into your VS Code workflow. It performs structural analysis to find similarities even if variables and formatting have changed.
Specialized Code Comparison Tools
If you need deeper analysis than a simple extension provides, these professional-grade tools are often used by developers:
- MOSS (Measure of Software Similarity): The academic “gold standard” for code comparison. It analyzes underlying logic rather than just text, so it isn’t fooled by renamed variables or reordered functions. It is typically used for batch submissions (e.g., checking an entire project against a database).
- JPlag: An open-source tool that can be run locally. Because it runs on your machine, your code is never uploaded to a third-party server, making it a favorite for privacy-conscious developers.
- Dolos: A modern tool that provides visual reports and “fingerprinting” to ignore template or boilerplate code, ensuring you only check the logic you’ve written.
Web-Based Alternatives
If you prefer not to install an extension, you can quickly check snippets using these web platforms:
- Copyleaks Programming Code Checker: Best for a quick multi-language check.
- Codequiry: Best for solo student checks and web-source matching (e.g., checking against GitHub or Stack Overflow).
Setting up a plagiarism checker in VS Code also depends on whether you want a seamless extension experience or a more powerful API/CLI integration.
1. AntiPlagiarism (Extension)
This is the most straightforward “plug-and-play” option for internal code duplication checks.
- Setup:
- Open the Extensions view in VS Code (Ctrl+Shift+X).
- Search for “AntiPlagiarism” and click Install.
- Once installed, open the AntiPlagiarism window from the Tools menu (or via the Command Palette: Ctrl+Shift+P).
- Select your Comparison Source (e.g., “Current Solution” or a specific folder) and click Run.
- Pricing: Generally free and open-source for local use.
2. Copyleaks (API/Enterprise Integration)
Copyleaks is better for checking against external web sources and AI-generated code.
- Setup:
- Register for a free account at Copyleaks.com to get your API Key.
- While they have a Google Docs add-on, for VS Code, you typically use their API or CLI tool to scan your workspace.
- You can also use the Copyleaks Web Interface to upload your .cpp, .py, or .java files directly.
- Pricing:
- Free: Limited characters (approx. 25,000) for basic scans without logging in.
- Paid: Uses a credit-based system. Prices vary by volume, typically targeting enterprises and schools.
3. Codequiry (Pro/Academic Grade)
Codequiry is highly accurate and specifically designed for source code, resisting variable name changes or reordering.
- Setup:
- Sign up at Codequiry.com to access the dashboard.
- Use their CLI tool for direct integration into your VS Code terminal to run scans across your entire project.
- Pricing:
- Individual Plans: Often start around $10–$20/month for a set number of checks.
- Enterprise/LMS: Customized pricing based on the number of students or submissions.
Quick Comparison (2026)
| Tool | Best For | Detection Type | Cost |
| AntiPlagiarism | Local Refactoring | Exact/Structural matches within your files | Free |
| Copyleaks | Web & AI Detection | Multi-source web + AI-generated code | Credit-based |
| Codequiry | High Accuracy | Logic patterns, variable renaming resistance | Subscription |
| MOSS | Academic Batching | Peer-to-peer logic similarity (Stanford) | Free |
Good tool @ GitHub: https://github.com/marketplace/actions/duplicate-code-detection-tool