MOSS-compatible · Free · Uncongested

A free MOSS-compatible server,
powered by Codequiry Hexagram.
Works with every MOSS client.

Codequiry Hexagram is our own code-similarity engine — an independent, winnowing-style fingerprinter that speaks the open MOSS client protocol. So moss.pl, mossum, moss.py, and every other open-source MOSS client work out of the box. Free for educators, students, and researchers. No queue. No daily caps.

✓ Free forever ✓ No credit card ✓ Educators & students welcome
⭐ Codequiry secures 1,000+ computer science courses worldwide for code plagiarism detection 🌍 Universities in 40+ countries
24+
Languages
0
Queue Wait
5+
Public Clients
$0
Cost
Hexagram by Codequiry

Our own code-similarity engine — built for the modern classroom.

Code-similarity detection (the approach popularized by MOSS) is the gold standard for catching peer-to-peer code copying in programming courses. Codequiry Hexagram is our independent implementation — a winnowing-style fingerprinter we built from scratch — exposed through the open MOSS client protocol so every existing MOSS client works with it unchanged. It's what the Codequiry platform uses for its peer-similarity scan, now offered as a free standalone service to the CS education community.

⚡

Winnowing-style fingerprints

Token-level fingerprinting that resists variable renaming, whitespace changes, and cosmetic edits — a class of obfuscations that defeat naive diff-based tools.

👥

Peer-to-peer focus

Compares every submission in a class against every other submission. Ideal for introductory programming courses and structured algorithmic assignments where similarity patterns emerge.

🧹

Base code filtering

Supply starter code, templates, or standard library imports as base files — Hexagram excludes them from the similarity score so you only see what students actually wrote.

📄

Familiar HTML reports

Results arrive as a ranked HTML report with side-by-side code panes highlighting matched passages — exactly the format your MOSS client expects. Open in any browser.

🔒

Private by default

Result URLs contain random tokens and aren't indexed. Only the person who submitted sees the link. Reports expire after 14 days.

🎓

Battle-tested on Codequiry

Hexagram is the same peer-similarity engine that powers Codequiry's commercial platform, already trusted by 1,000+ CS courses worldwide. You're getting production-grade tech.

Why use our server

MOSS-compatible. Dedicated infrastructure. Zero queue.

The classic shared academic code-similarity endpoint enforces a 100-submissions-per-day-per-user cap and frequently queues during midterms and finals week. The Codequiry Hexagram server is sized for bursty academic workloads and speaks the same client protocol — so your existing MOSS tooling keeps working, just faster.

🚀

Uncongested servers

Dedicated infrastructure sized for bursty academic workloads. No “queue full” errors during peak semester-end crunch. No throttling. Results in seconds, not hours.

♾️

No daily cap wait

Our free tier is generously sized for classroom use. Submit your full class of assignments without hitting the restrictive 100-file daily caps of legacy academic servers.

🔌

Drop-in compatible

Hexagram speaks the open MOSS client protocol. Change one variable in your existing moss.pl script (or mossum, moss.py, etc.) and you're done.

🌎

Global low-latency

Servers sized to reduce round-trip time for international submitters. Upload and download results at full bandwidth — no bottleneck of a single shared academic server.

🛡️

Private by default

Result URLs use random tokens and aren't indexed. Submissions are processed transiently for fingerprinting and aren't retained or used to train any model.

🏫

Trusted by 1,000+ courses

Hexagram is the same similarity engine Codequiry runs in production for over 1,000 computer science courses worldwide. Production-grade reliability, free for academic use.

Endpoint & Clients

Works with every open-source MOSS client on GitHub.

Hexagram implements the open MOSS client protocol — the de-facto standard for academic code-similarity workflows. Keep using moss.pl, mossum, moss.py, or any custom client you already wrote. Point it at our endpoint (sent to you after access is granted) and it works unchanged.

server.credentials
Endpoint 🔒 Revealed after access
User ID 🔒 Sent by email
Protocol MOSS standard (compatible with Stanford clients)
Languages 24+ supported — see list below

Public MOSS clients on GitHub

Open-source, community-maintained. Point any of them at our endpoint.

PL
moss.plPerl
The classic Perl submission script circulated throughout the CS education community — the reference client for the MOSS protocol.
PY
mossumPython
Wraps MOSS and produces beautiful graph visualizations of similarity clusters. Great for spotting groups of copying students.
PY
moss.pyPython
Clean Pythonic wrapper over the MOSS protocol. Simple API for programmatic submission and result fetching.
PY
mossnetPython
Network analysis tool built on MOSS results. Extracts similarity graphs for cluster detection workflows.
JS
moss-js & friendsNode
Various Node.js wrappers exist on GitHub for integrating MOSS into JavaScript toolchains and CI pipelines.
CLI
moss-cli / customAny
The MOSS protocol is simple enough that many instructors write their own thin wrapper. All of them work with our endpoint.

Example: submitting with moss.pl

Your existing script works unchanged — just swap in the endpoint we email you.

~/course/assignment1 — bash
$ ./moss -l java -d submissions/*.java # Point moss.pl at our endpoint (sent via email after access): # $server = "<your-codequiry-endpoint>"; # $userid = "<your-id>"; Checking files... Uploading submissions/student_01.java...done. Uploading submissions/student_02.java...done. Query submitted. Results at: https://<codequiry-moss>/results/8472610394
Get started

Free access in three minutes.

No installation on our side. No contracts. Request access and we'll email you everything you need to point any MOSS client at our server.

01

Request access

Drop your email in the form above. We verify it's a real educator, student, or researcher inbox and approve it — usually within an hour during work days.

02

Receive your endpoint

You get an email with the server URL, your user ID, and links to the most common MOSS clients. Set it in moss.pl or your client of choice — two lines to change.

03

Submit & review

Run your usual MOSS command on a folder of submissions. Open the HTML report, sort by similarity, and dig into the side-by-side view. That's it.

Supported Languages

24+ languages, from Python to MIPS assembly.

MOSS was designed to analyze code structure, not just text — so it handles everything from modern scripting languages to hardware description languages and assembly dialects.

C C++ Java C# Python JavaScript Visual Basic FORTRAN ML Haskell Lisp Scheme Pascal Modula2 Ada Perl TCL MATLAB VHDL Verilog Spice MIPS assembly 8086 assembly HCL2
The 2026 plagiarism problem

MOSS catches peer copying. But students don't just copy from peers anymore.

MOSS was built in 1994. The internet wasn't what it is today. There was no ChatGPT, no GitHub, no Stack Overflow, no Chegg. Modern students cheat in three ways — and MOSS was only designed to catch one of them.

ChatGPT Claude GitHub Copilot Gemini GitHub repos Stack Overflow Chegg CourseHero GeeksforGeeks LeetCode solutions Reddit (r/learnprogramming) Quora Bartleby StudyBlue

MOSS, by design, cannot see any of these. You need web + AI scans to catch them — which is exactly why we built Codequiry.

The complete picture

Three scan types. One submission. The whole cheating surface covered.

Codequiry runs all three checks in a single scan — MOSS-style peer similarity, web plagiarism across GitHub and Stack Overflow, and AI code detection for ChatGPT/Claude/Copilot. No other academic tool combines all three.

① Peer Similarity

MOSS + Zeus engine

Every submission compared against every other submission in the batch — plus a historical corpus if you want. MOSS-grade fingerprinting, enhanced with our Zeus engine for 65+ languages.

  • Winnowing + k-gram fingerprinting
  • Resistant to renaming & cosmetic edits
  • Base code / template filtering
  • Historical cross-semester comparison
② AI Detection

ChatGPT, Claude, Copilot

Our AI code detector is trained specifically on code — not text. It flags snippets generated by ChatGPT, Claude, Gemini, GitHub Copilot, and other LLMs with confidence scoring per region.

  • LLM code detection (not general-purpose)
  • Per-function confidence regions
  • Handles mixed human + AI code
  • Updated as new models release
③ Web Plagiarism

GitHub, SO & cheating sites

We scan your submissions against 1 trillion+ indexed sources — including every public GitHub repo, Stack Overflow, Chegg, CourseHero, GeeksforGeeks, LeetCode solutions, and the broader open web.

  • 1T+ sources including GitHub & SO
  • Catches code from cheating sites
  • Crosses language boundaries (JS ↔ TS)
  • Shows exact source URLs
1,000+

Computer science courses worldwide rely on Codequiry

From community colleges to the top research universities — instructors in 40+ countries use Codequiry to keep CS assignments honest in the age of AI.

🇺🇸 🇬🇧 🇨🇦 🇦🇺 🇩🇪 🇫🇷 🇳🇱 🇸🇪 🇸🇬 🇮🇳 🇧🇷 🇯🇵 🇰🇷 🇪🇸 🇮🇹 🇨🇭
Who uses this

Built for the people running CS courses.

The Free MOSS Server is for anyone who needs quick, reliable, local similarity checking — without the congestion and daily caps.

🧑‍🏫

CS professors & instructors

Grade a batch of intro-programming assignments without waiting in Stanford's peak-week queue. Run MOSS immediately, flag suspicious pairs, move on.

🧑‍💻

Teaching assistants & graders

Scripted workflows via mossum or moss.py to triage hundreds of submissions. Uncongested server means no retries during finals week.

🔬

Researchers

Studying code similarity, clone detection, or programming-language evolution? MOSS is the academic baseline. Use our server for reproducible, throttle-free experiments.

🏫

Bootcamps & online programs

Commercial education providers normally need Stanford's paid tier. Use our free server for non-commercial project similarity, upgrade to Codequiry for AI + web checks.

📚

Academic integrity offices

Need a second opinion on a reported case? Run MOSS independently on our server to cross-verify findings from your institution's primary tool.

🎓

Students (self-check)

Working on a group project and worried about accidental similarity with a partner? Run MOSS on your own code before submitting. Ethical self-review.

Comparison

Legacy academic server vs. Hexagram vs. Codequiry Platform.

If you just need fast, MOSS-client-compatible peer similarity, Hexagram alone is enough. For catching code copied from the web or generated by AI, you'll want the full Codequiry platform.

Feature
Legacy academic server
Hexagram (Free)
Codequiry Platform
Code similarity (MOSS-style)
✓
✓
✓
Free to use
✓
✓
Free trial
Dedicated infrastructure (no queue)
—
✓
✓
100 files/day cap
Enforced
Relaxed
Unlimited
Web plagiarism (GitHub, SO, Chegg)
—
—
✓ 1T+ sources
AI code detection (ChatGPT, Claude, Copilot)
—
—
✓
Dashboard & LMS sync
—
—
✓ Canvas, Moodle
Works with moss.pl / mossum
✓
✓
Web / API
Trusted by 1,000+ CS courses worldwide
—
✓
✓
For the full picture

Hexagram catches peers.
Codequiry catches the web + AI too.

Get all three scans in a single submission — Hexagram peer similarity, AI code detection for ChatGPT and Claude, and web plagiarism against GitHub, Stack Overflow, and every major cheating site. Already trusted by 1,000+ CS courses worldwide.

✓Peer similarity (Hexagram + Zeus)
✓AI detection (ChatGPT, Claude, Copilot)
✓Web search: GitHub, SO, Chegg, more
✓65+ languages, no file caps
✓LMS integration (Canvas, Moodle)
✓Dashboard & historical tracking
Start Free Trial — No Card Required
Free trial · Full access to all three scan types · Cancel anytime
FAQ

Frequently asked questions.

What is the Free MOSS-Compatible Server?
It's a free code-similarity server powered by Codequiry Hexagram, our own code-similarity engine. Hexagram speaks the open MOSS client protocol — the de-facto standard used throughout CS education — so any existing MOSS-compatible client works with it out of the box.
Is this the same as Stanford's MOSS service?
No. Codequiry Hexagram is our own independent code-similarity engine. MOSS (Measure of Software Similarity) is a trademark of Stanford University for their separately operated service. Hexagram is compatible with the open MOSS client protocol, but it is not Stanford's service and is not affiliated with or endorsed by Stanford University.
Is the Codequiry Free Server really free?
Yes. Free access is open to educators, students, and researchers. Request access with your email — we'll send your endpoint and client instructions. No credit card, no trial expiry.
Why use Hexagram instead of a legacy academic server?
Legacy shared academic servers enforce a 100-submissions-per-day-per-user cap and often queue during peak academic periods. Hexagram runs on dedicated, uncongested infrastructure sized for bursty classroom workloads — so your submissions process immediately.
Which MOSS clients work with your server?
Any open-source client that speaks the MOSS client protocol. Works with the classic moss.pl Perl script, mossum (Python visualization wrapper), moss.py, mossnet, and any custom client you've written. Change one variable — the server URL — and you're done.
What languages does Hexagram support?
Hexagram supports 24+ languages including C, C++, Java, C#, Python, JavaScript, TypeScript, Go, Rust, Swift, Kotlin, Ruby, PHP, Visual Basic, FORTRAN, Haskell, Scheme, Pascal, Ada, Perl, MATLAB, VHDL, Verilog, and common assembly dialects.
Is code-similarity detection enough for modern plagiarism?
Similarity engines (like Hexagram) are excellent for local peer-to-peer similarity — comparing a class of student submissions against each other. They are not designed to catch code copied from the web (GitHub, Stack Overflow, Chegg, CourseHero) or AI-generated code from ChatGPT, Claude, and Copilot. For modern CS courses where all three cheating vectors matter, use the full Codequiry platform which combines peer similarity with web and AI detection in a single scan.
Does Hexagram detect ChatGPT or AI-generated code?
Hexagram, like any MOSS-style similarity engine, detects similarity between the files you submit — not AI authorship. To catch ChatGPT, Claude, Gemini, and Copilot output, use Codequiry's AI code detector, which runs alongside similarity and web scans on the full platform.
Can Hexagram find code copied from GitHub or Stack Overflow?
No — similarity engines only compare the submissions you give them against each other. They don't crawl or index the public web. For that you need Codequiry's web plagiarism scan, which indexes 1 trillion+ sources including every public GitHub repo, Stack Overflow, Chegg, CourseHero, and major cheating sites.
How long do results stay on the server?
Result URLs are typically retained for 14 days — consistent with standard MOSS client expectations. Save or export reports you need to keep.
Can I use this for commercial purposes?
The Free MOSS-Compatible Server is intended for educational and research use. For commercial code plagiarism detection with unlimited usage, web scanning, and AI detection, see the full Codequiry platform.
Do I need to install anything?
No. Download any open-source MOSS client (we recommend moss.pl or mossum for visualizations), plug in the endpoint and user ID we email you, and run it from your terminal. Works on Linux, macOS, and Windows via WSL.
Who actually runs this server?
Codequiry — the code plagiarism detection platform trusted by over 1,000 computer science courses worldwide. Hexagram is the same peer-similarity engine we run in production, offered here as a free standalone service to the CS education community. If you need web and AI detection on top, you can upgrade to our full platform anytime.

Trademark notice: MOSS (Measure of Software Similarity) is a trademark of Stanford University. Codequiry Hexagram is an independent code-similarity engine built by Codequiry; it is compatible with the open MOSS client protocol but is not Stanford's service and is not affiliated with or endorsed by Stanford University.

Request Access

Start running code-similarity checks on our uncongested server — in under three minutes.

Join the educators, students, and researchers already using the Codequiry Hexagram free server to keep their CS courses honest.

✓ Free forever ✓ No credit card ✓ Compatible with moss.pl, mossum, all clients

Need AI + web detection too? Start a free trial of Codequiry →