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Coda One vs GPTZero

An honest comparison to help you choose the right tool

Feature
Coda One
GPTZero
Free tier
Detector access in the web app (no card)
10,000 words/month (no card)
Per-sentence analysis
Yes
Yes
AI humanizer included
Yes, free
No
Signup required
No
No for free tier
Batch scanning
No
Yes — 10 file cap Essential, unlimited Premium+
File upload
.txt files
PDF, DOCX, TXT
API access
Planned
Yes, on Professional tier ($45.99/mo monthly or $24.99/mo annual)
Plagiarism detection
No
Included on Essential and above
Published accuracy figures
Yes — FPR, FNR and ROC AUC at /ai-detector/accuracy
Marketing accuracy figures; no per-register breakdown published
LMS integration
No
Yes (Canvas, etc.)
Entry paid — Essential
$9.99/mo monthly or $7.99/mo annual — Starter
$14.99/mo monthly or $8.33/mo annual (150K words/mo)
Premium tier
$19.99/mo monthly or $15.99/mo annual — Pro
$23.99/mo monthly or $12.99/mo annual (300K words/mo)
Professional tier
$39.99/mo monthly or $31.99/mo annual — Business
$45.99/mo monthly or $24.99/mo annual (500K words/mo, API)
Additional writing tools
Humanizer, Rewriter, Grammar Checker
None — detector only

GPTZero figures checked against their own pricing and product pages on 28 August 2026. They change these often; if you are deciding on the strength of a row, check theirs too. Our own figures come from the running code — free limits from the tool API, detector error rates from the published benchmark at /ai-detector/accuracy.

Why Choose Coda One?

One Loop, 4 Tools

AI Detector, AI Humanizer, AI Rewriter, Grammar Checker. Check a draft, then fix what the check finds -- without a second subscription.

Generous Free Tier

All 4 tools open directly in the browser with no signup. The AI Detector has no daily limit; the other three give you 3 free uses a day.

Text Is Not Kept

Used anonymously, the text you submit is not stored after the response is generated, and it is never used to train models.

Guides Around the Tools

Plus, explore our AI scenario guides, MCP server resources, and agent skills to get more from your tools.

GPTZero is one of the best-known AI detectors in education. It offers LMS integrations with Canvas, Blackboard, and other platforms, which makes it a practical fit for institutions that need dashboards, batch review, and admin controls.

Coda One takes a more direct browser-tool approach. Instead of centering the product on school administration features, it keeps the detector open in the web app and pairs it with a humanizer, rewriter and grammar checker.

Do not use Coda One's detector to decide anything about another person. We measured it against a deliberately hostile 48-sample corpus and published the result: it flags 4% of human writing as AI, misses 96% of AI writing, and scores a ROC AUC of 0.41 — below the 0.5 you would get from a coin toss on that corpus. If you are a teacher deciding whether a student cheated, we are not the tool, and honestly no detector is; GPTZero has the institutional workflow, the batch review and the audit trail, and if your school has a licence, use it. Choose Coda One for the opposite job: you wrote the draft, you suspect it reads like a machine wrote it, and you want to find the sentences that do. Free, no daily limit, 3,000 words a check, and every error rate on the table. GPTZero is what an institution runs on your writing. Coda One is what you run on your own.

Try It Yourself

See how Coda One's AI Detector compares in a browser-first workflow.

Try AI Detector Free

Frequently Asked Questions

How does Coda One compare with GPTZero?
Coda One is a better fit for individuals checking their own draft: the detector is free with no daily limit and a humanizer, rewriter and grammar checker sit beside it. GPTZero is the better fit for institutions that need LMS integrations, batch review and admin workflows — and for anyone whose decision affects someone else, because that use needs an audit trail we do not provide.
What is free on GPTZero?
GPTZero gives 10,000 words a month of detection free, with no credit card and no signup required. Coda One gives unlimited checks with no daily cap, at 3,000 words per check. Theirs is a monthly budget; ours is a per-check ceiling with no monthly total, so which is more generous depends on whether you check often or check long documents.
Which detector is more accurate?
We can only answer honestly for ours, and the answer is that it is weak. On a 48-sample adversarial corpus at the default threshold it produced 1 false positive out of 24 human samples (4%) and missed 23 of 24 AI samples (96%), with a ROC AUC of 0.41 — below chance on that corpus. The full method, the samples and the caveats are at /ai-detector/accuracy. We have no comparable figure for GPTZero: their terms forbid the automated testing that would produce one, so any number we quoted would be invented, and we would treat a competitor quoting one about us the same way. Treat every AI detector, ours included, as a hint about how text reads rather than evidence of who wrote it.
Does GPTZero offer humanization?
No. GPTZero is a detection-only tool. Coda One puts detection and humanization in one place, which is convenient — though it is worth being clear that a low score from our own detector after our own humanizer is not evidence of much. It is the same engine grading its own work.
Which should teachers use?
GPTZero, or whatever your institution licenses — and then not as proof. If your school has no licence, please do not substitute ours: on our own benchmark it missed 23 of 24 AI samples, so it will clear almost every AI submission it sees, while flagging 1 of 24 human ones. Coda One is built for the writer checking their own draft, not for the person grading it.
How accurate is each tool for non-English text?
Coda One is English-only and should not be used on anything else: the phrase patterns, dash density and sentence-rhythm signals it weighs are all calibrated on English, and our published benchmark contains no non-English samples at all. GPTZero advertises multilingual detection; we have not tested it and cannot tell you how well it holds up. The wider field has no strong multilingual detection benchmark, so treat non-English results from any detector as noise.
What document formats does each tool support?
GPTZero supports PDF, DOCX, and TXT file uploads, which is helpful for teachers reviewing submitted documents directly. Coda One currently accepts plain text and TXT file input. If you need to paste text from a Word document, both work fine; if you need to upload a PDF directly for detection, GPTZero has the advantage.

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