Code Plagiarism API

The modern
MOSS alternative

Codequiry API delivers production-grade code plagiarism detection with Hexagram Tokenization™, JSON responses, and web-scale matching — everything Stanford MOSS doesn't offer.

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65+
Languages
15M+
Files Analyzed
<2min
Avg Response
99.7%
Accuracy
Why Codequiry API

Built for educators who demand more

Unlike legacy tools, Codequiry delivers modern infrastructure with web-scale capabilities and real-time results.

Hexagram Tokenization™

Our proprietary 6-dimensional semantic analysis understands code meaning, not just syntax. Resilient to renaming, formatting, reordering, and obfuscation techniques that fool other tools.

Web-Scale Matching

Search GitHub, Stack Overflow, forums, and billions of indexed sources. Catch what offline tools miss.

Clean JSON API

Modern REST API with structured JSON responses. Parse in any language, store in any database.

Parallel Processing

Horizontally scaled infrastructure delivers results in under 2 minutes, even for 100+ submissions.

SDKs, Webhooks & CI/CD Ready

Native SDKs for Node.js, Python, PHP, and Java. Webhooks for async workflows. Built for integration into your existing pipeline — whether that's an LMS, contest platform, or CI system.

Understanding the Problem

What is Source Code Plagiarism?

Source code plagiarism occurs when programmers copy, modify, or disguise code from other sources without proper attribution. In academic settings, this includes students copying homework assignments, sharing solutions, or using code from GitHub, Stack Overflow, or online tutorials without permission.

Code plagiarism detection tools analyze source code to identify similarities between submissions. Unlike text plagiarism checkers, code plagiarism detectors must understand programming language syntax, variable naming, code structure, and algorithmic patterns to accurately identify copied code — even when it has been modified.

Common code obfuscation techniques include renaming variables and functions, reordering statements, adding dead code, changing formatting, and restructuring loops. Advanced plagiarism detection systems like Codequiry's Hexagram Tokenization™ can detect these modifications by analyzing semantic meaning rather than just syntax.

What is Stanford MOSS?

MOSS (Measure of Software Similarity) is a free code plagiarism detection system developed at Stanford University by Alex Aiken. Since 1994, MOSS has been the de facto standard for detecting copying in programming assignments.

MOSS works by converting source code into a fingerprint using a technique called "winnowing" and comparing fingerprints to find similarities. While revolutionary for its time, MOSS has significant limitations:

  • HTML-only results — no JSON API for automation
  • Offline only — doesn't check web sources
  • Basic obfuscation detection — easily fooled
  • Limited language support — missing modern languages
  • No webhooks or SDKs — manual process only
The Modern Choice

Why Educators Switch from Stanford MOSS to Codequiry

MOSS was revolutionary in 1994. But modern code plagiarism detection requires modern infrastructure.

MOSS Limitations

  • Returns HTML pages, not JSON data
  • Only compares uploaded files — no web search
  • Basic fingerprinting easily fooled by renaming
  • Email-based submission system
  • No API, SDKs, or webhooks
  • Single-threaded, slow processing
  • Limited to ~25 programming languages

Codequiry Advantages

  • Clean JSON API responses
  • Web-scale matching (GitHub, StackOverflow, etc.)
  • Hexagram Tokenization™ anti-obfuscation
  • REST API with instant responses
  • SDKs for Node, Python, PHP, Java
  • Parallel processing — 50x faster
  • 65+ programming languages supported

Perfect For

  • Universities: CS departments, academic integrity
  • Bootcamps: Automated homework checking
  • Contests: Hackathon & competition judging
  • Hiring: Technical interview validation
  • Enterprise: IP protection & code audits
  • CI/CD: Automated PR checking
Comparison

See how we stack up

A side-by-side look at what each tool actually delivers.

Capability Codequiry Stanford MOSS JPlag DoloS
JSON API Responses Yes HTML only Partial Partial
Web & Repository Matching Yes Offline Offline Offline
Anti-Obfuscation Detection Advanced Basic Basic Basic
SDKs & Webhooks Full None Limited Limited
65+ Language Support Yes Some Some Some
Unlimited Plans Available $49/mo Limits Limits Limits
View Detailed Comparison
Quick Start

Integrate in minutes

Four simple API calls: create, upload, start, and get results. Our comprehensive documentation covers every endpoint, parameter, and use case.

Full API Documentation
Create Check → Upload → Start → Get Results →
api-example.js
const response = await fetch('https://codequiry.com/api/v1/check/create', {
  method: 'POST',
  headers: {
    'Accept': 'application/json',
    'apikey': process.env.CODEQUIRY_API_KEY
  },
  body: JSON.stringify({
    name: 'Assignment 1',
    language: 'python'
  })
});

const { check_id } = await response.json();
// Upload files, start check, get JSON results...
Language Support

Code Plagiarism Detection for 65+ Programming Languages

From Python homework assignments to enterprise Java codebases — we've got you covered.

Python

Java

JavaScript

C / C++

Rust

Go

Swift

Ruby

Also supported: TypeScript, Kotlin, Scala, PHP, C#, MATLAB, R, Perl, Haskell, OCaml, Erlang, Elixir, Lua, Dart, Julia, Fortran, COBOL, Assembly, SQL, Shell/Bash, PowerShell, and 30+ more.

Use Cases

How Organizations Use Code Plagiarism Detection

From university classrooms to enterprise code audits — real-world applications of source code similarity checking.

Academic Integrity in CS Education

Computer Science professors use code plagiarism detection to identify copied programming assignments, shared homework solutions, and code from online sources. Codequiry integrates with LMS platforms like Canvas, Blackboard, and Moodle to automate the checking process.

Programming Contest Validation

Hackathons, coding competitions, and online judges use source code similarity detection to ensure submissions are original. Codequiry's web matching catches participants who copy solutions from GitHub, LeetCode, or previous contest archives.

Technical Interview Screening

Hiring platforms integrate code plagiarism APIs to validate take-home coding tests and live coding challenges. Detect candidates who copy solutions from the web or share answers between interview rounds.

Enterprise IP Protection

Legal and security teams audit codebases to identify copied code, license violations, and potential IP theft. Codequiry helps enterprises protect proprietary algorithms and detect unauthorized code reuse in contractor deliverables.

Bootcamp & MOOC Assessment

Coding bootcamps and online learning platforms ensure students complete assignments independently. Automated plagiarism detection at scale — check thousands of submissions per week without manual review.

CI/CD Pipeline Integration

DevOps teams add code similarity checks to pull request workflows. Automatically flag suspicious commits, detect accidental license violations, and ensure code originality before merging to main branches.

Frequently Asked Questions

Code Plagiarism Detection FAQ

What is the best Stanford MOSS alternative?

Codequiry is the leading MOSS alternative for code plagiarism detection. Unlike MOSS, Codequiry provides JSON API responses, web-scale matching, anti-obfuscation detection via Hexagram Tokenization™, and support for 65+ programming languages. It's designed for modern workflows with SDKs and webhooks.

How does source code plagiarism detection work?

Source code plagiarism detection works by tokenizing code into structural patterns, then comparing these patterns across submissions. Codequiry's Hexagram Tokenization™ uses 6-dimensional semantic analysis to understand code meaning — detecting plagiarism even when variables are renamed, code is reformatted, or statements are reordered.

Is this Stanford's MOSS service?

No. Codequiry is an independent alternative to Stanford MOSS, built from scratch with modern technology. While MOSS was pioneering in 1994, Codequiry offers significant improvements: JSON APIs, web matching, advanced anti-obfuscation, webhooks, and 65+ language support.

What programming languages are supported?

Codequiry supports 65+ programming languages including Python, Java, C/C++, JavaScript, TypeScript, Go, Rust, Swift, Kotlin, Ruby, PHP, C#, Scala, MATLAB, R, Haskell, and many more. Language auto-detection is included for mixed-language projects.

How accurate is code plagiarism detection?

Codequiry achieves 99.7% accuracy in detecting code similarities. Our Hexagram Tokenization™ technology is designed to catch sophisticated obfuscation techniques including variable renaming, code reordering, dead code insertion, formatting changes, and comment modifications.

Can I detect code copied from GitHub or Stack Overflow?

Yes. Unlike MOSS and other offline tools, Codequiry includes web-scale matching that searches billions of indexed sources including GitHub repositories, Stack Overflow answers, online tutorials, forum posts, and code hosting platforms.

How does Codequiry compare to JPlag and DoloS?

Codequiry offers advantages over JPlag and DoloS including web matching (not just peer comparison), JSON API responses, webhooks for async workflows, more language support, and commercial SLAs. All three are alternatives to MOSS, but Codequiry is purpose-built for API integration.

What's the pricing for code plagiarism detection?

Codequiry offers a free tier with daily limits, and paid plans starting at $49/month with 1,560 checks. All plans include web scanning, JSON results, SDKs, and priority support. Enterprise plans add SSO, dedicated infrastructure, and custom SLAs.

Can I integrate with my LMS or CI/CD pipeline?

Absolutely. Codequiry provides a REST API with SDKs for Node.js, Python, PHP, and Java. Webhooks notify your systems when results are ready. Integrate with Canvas, Blackboard, Moodle, GitHub Actions, GitLab CI, Jenkins, or any custom workflow.

How fast is the plagiarism analysis?

Codequiry delivers results in under 2 minutes for most checks, even with 100+ submissions. Our horizontally-scaled infrastructure processes checks in parallel — 50x faster than single-threaded tools like MOSS. Large batch processing and webhooks are available for high-volume workloads.

Alternatives Compared

MOSS Alternatives: Which Code Plagiarism Detector is Best?

When searching for alternatives to Stanford MOSS, educators and developers typically consider JPlag, DoloS, and Codequiry. Each tool has different strengths for source code plagiarism detection.

JPlag is an open-source tool from KIT that focuses on pair-wise comparison. DoloS uses AST analysis for structural comparison. Both are offline tools without web matching.

Codequiry is the only API-first solution with web-scale matching, JSON responses, and Hexagram Tokenization™ for advanced anti-obfuscation. It's designed for modern integration workflows.

Quick Comparison

Stanford MOSS Free, HTML only, offline
JPlag Open-source, self-hosted, offline
DoloS AST-based, self-hosted, offline
Codequiry JSON API, web matching, cloud
Full Comparison Guide

The Best MOSS Alternative for Code Plagiarism Detection

Join 5,000+ developers and educators using Codequiry for source code plagiarism detection. Get your API key and start detecting copied code with web-scale accuracy.

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Free tier available No credit card required JSON responses