Textlume vs GPTZero

GPTZero alternative

GPTZero is an AI detector built around classrooms, with writing replay and school integrations. Textlume reads a text with a score, a range and a mark on every sentence, then lets you rework it in the same editor. Here is how the two differ, with every GPTZero fact taken from its own pages.

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The short answer

Choose GPTZero if your school already works in Google Classroom or Canvas, or if you need a replay of how a document was typed. Choose Textlume if you want to see which sentences drive a score and then edit the text with a humanizer, paraphraser or grammar checker in one place. We have not tested GPTZero ourselves, so this page compares features, limits and prices. It makes no accuracy claim about either tool.

Where the two really differ

Classroom tools. GPTZero connects to Google Classroom, Canvas and Google Docs and can replay how a document was written. Textlume reads the finished text.
What comes after the reading. GPTZero's product menu has no humanizer. Textlume keeps a humanizer, a paraphraser and a summarizer next to the detector.
Languages. GPTZero names five languages it fully supports. Textlume is calibrated for 13 text languages and marks any other language as not calibrated.
Accuracy figures. GPTZero publishes a 99.9% figure of its own. Textlume publishes held-out counts per language, with sample sizes. Neither figure was measured on the other tool.
Price display. GPTZero shows its prices in your local currency. Textlume charges one USD list price in every country, from 6.99 USD a month billed yearly.

GPTZero and Textlume side by side

Feature	GPTZero	Textlume
Free tier	Scans up to 10,000 characters without an account. Longer scans need a free account.	1 free run a day per tool, up to 250 words in the detector and 150 in the humanizer. No account, no card.
Price	Shown in the visitor's local currency. Yearly billing is marked as a 45% saving.	From 6.99 USD a month billed yearly, or 9.99 USD month to month.
Words and limits	Team plan: 500,000 words per member a month. API plans from 300,000 words a month.	Detector: 50,000 to 300,000 words a month, up to 10,000 per check. Humanizer: 10,000 to 50,000 words a month.
Languages	Full support for English, German, Portuguese, French and Spanish, by its own FAQ.	13 calibrated text languages for AI detection. Other languages get no score.
Published accuracy figures	Claims 99.9% accuracy, from its own and partner benchmarks.	Held-out counts per language, with sample sizes, on our accuracy page.
Sentence marks	Highlights sentences and gives a confidence score.	Yes. Every sentence gets a score, next to an overall score with a range and a confidence rating.
Humanizer	None in its product menu.	Yes. Academic, professional and casual tabs, and names, numbers and quotes stay as they are.
API	Yes, sold in monthly word plans.	On the Pro plan, for detection, humanizing, paraphrasing, summaries and grammar.
Plagiarism check	Yes, sold as Plagiarism Check.	Coming soon. Not open for checks yet.

What GPTZero and Textlume cost

GPTZero

Professional TeamLocal currency
Monthly
500,000 words per member a month, shared team credits, at least 2 seats, card payment.
APILocal currency
Monthly
From 300,000 words a month, batches of 50 files, up to 150,000 characters per document.

Textlume

Basic6.99 USD
Per month, billed yearly. Monthly: 9.99 USD.
50,000 detector words, 10,000 humanizer words and 10,000 paraphraser words a month, plus 20 runs of clarity suggestions a day.
Plus9.99 USD
Per month, billed yearly. Monthly: 19.99 USD.
150,000 detector words, 25,000 humanizer words and 25,000 paraphraser words a month, plus 30 runs of clarity suggestions a day.
Pro12.99 USD
Per month, billed yearly. Monthly: 29.99 USD.
300,000 detector words, 50,000 humanizer words and 50,000 paraphraser words a month, plus 40 runs of clarity suggestions a day. API access included.

Where GPTZero is ahead

Writing Replay shows how a document was typed in Google Docs, which no reading of the finished text can show.
A Chrome extension and links to Google Classroom, Canvas and Zapier put the check inside tools many schools already run.
Its free scan box takes up to 10,000 characters without an account, more text than our free daily check of 250 words.
Its API is sold in large monthly word volumes, starting at 300,000 words.

How Textlume works

Every result gives a score with a range, a confidence rating and a mark on each sentence. It reads as a probability, never as proof.
The detector is calibrated for 13 text languages. A text in any other language gets no score, only a note that the language is not calibrated.
Our accuracy page lists how often human texts were flagged in a held-out test, per language and with sample sizes, including writing by non-native speakers.
A humanizer, a paraphraser, a summarizer and a free grammar checker sit in the same editor as the detector.
Texts from signed-out visitors are not stored.

Which one suits your work

Pick GPTZero if

you teach and want checks inside Google Classroom or Canvas, a replay of how a document was written, or an API with large monthly word volumes.

Pick Textlume if

you want a sentence-by-sentence reading with a range and a confidence rating, published false-flag counts per language, and rewriting tools next to the detector, from 6.99 USD a month billed yearly.

Questions people ask before choosing

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Is GPTZero accurate?

GPTZero says its detector reaches a 99.9% accuracy rate on its own and partner benchmarks, and that it trains false positives on ESL writing down to 1%. Those are its figures. We have not tested GPTZero, so we can neither confirm nor dispute them. GPTZero itself says results should not be used to punish students, and that accuracy is higher on longer texts and English prose.

How much does GPTZero cost?

GPTZero shows its prices in the visitor's local currency, so the figure depends on where you are. Its pricing page offers monthly or yearly billing, with yearly marked as a 45% saving, and its team plan gives 500,000 words per member a month. Textlume charges the same USD list price everywhere, from 6.99 USD a month billed yearly or 9.99 USD month to month.

Is GPTZero free?

For short texts, yes. Its scan box takes up to 10,000 characters without an account, and longer scans need a free account. The free Textlume check reads 250 words, 1 time a day, with no account and no card.

What is the difference between GPTZero and Turnitin?

Anyone can sign up for GPTZero. Turnitin does not sell individual licences and reaches students through their school or university. Both put an AI score in front of a person who has to judge it, and both say a score alone should not decide a case.

Does GPTZero have a humanizer?

No. Its product menu lists an AI detector, a plagiarism check, a grammar checker, writing replay and a few other tools, but no humanizer. Textlume has one. It keeps names, numbers and quotes as they are, and it makes no promise that the result passes any detector.

Which languages does GPTZero support?

Its FAQ names English, German, Portuguese, French and Spanish as fully supported. Textlume is calibrated for 13 text languages and marks a text in any other language as not calibrated, so you know when a score rests on less.

Does GPTZero keep my text?

Its FAQ says documents sent through the API are not stored, while inputs from the dashboard are stored and used in aggregate to improve the service. On Textlume, nothing a signed-out visitor pastes is stored, and signed-in members can switch their history off or delete it.

Is GPTZero part of Grammarly now?

GPTZero announced in 2026 that it is joining Superhuman, the company that also runs Grammarly, and said nothing changes for its daily users. Its site footer now links to both Superhuman and Grammarly.

Will Textlume give the same score as GPTZero?

Not necessarily. The two use different models and different lines for calling a text AI-written, and we have not compared them on the same texts. Treat each score as one reading of the text, never as a verdict.

Does Textlume have a plagiarism check like GPTZero?

Our plagiarism check is coming soon and not live yet. Once it opens, it will search the open web on paid plans. GPTZero already sells one, called Plagiarism Check.

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