Compare AI detectors
isGenAI vs GPTZero: a different kind of AI checker
GPTZero is an AI text classifier: it estimates what share of a document is AI-written, highlights sentences and offers plagiarism checks, free without an account up to 10,000 characters. isGenAI does not estimate authorship. It finds declared AI use, such as “drafted with ChatGPT”, shows the exact sentence, and reads C2PA, AI labels and saved prompts in images, free with no account.
isGenAI (isgenai.com) is not affiliated with GPTZero. Looking for GPTZero itself? Go to gptzero.me.
If you need a probability that unlabelled text came from a language model, GPTZero is built for that and isGenAI is not. If you need evidence you can quote back to an author, or you also have images to check, read on.
isGenAI and GPTZero compared
| Question | isGenAI | GPTZero |
|---|---|---|
| Free use | Free, up to 16,000 characters per check. | Up to 10,000 characters without an account; a free account checks longer texts and batches of files. (source) |
| Sign-up | None. No account, no email. | Not needed under 10,000 characters; a free account above that. (source) |
| Paid plans | None needed. | Paid individual and team plans are listed on its pricing page, with a discount for annual billing. (source) |
| Method | Finds declared AI use, such as “drafted with ChatGPT”, and shows the exact sentence. It keeps a mere mention of a tool apart from a statement of use and gives no writing-style probability. | A proprietary model that weighs many signals, including perplexity and burstiness, and estimates the share of AI text. (source) |
| Result | The matching sentences, labelled as declared use, tool mention or code integration. | Human, mixed or AI classification with probabilities, a confidence category and highlighted sentences. (source) |
| Images and code | Images: C2PA, IPTC labels and saved prompts. Code: declared AI use and AI-library imports. | Its text pages do not describe code detection. (source) |
| Plagiarism | Not offered. | Separate plagiarism check. (source) |
| API | POST /v1/check with a file, URL, text or code. No API key for the documented endpoints. | Text prediction API with an x-api-key header. (source) |
| Privacy | Pasted text and code are private by default; the exported report leaves the pasted content out. | API documents are not stored; dashboard inputs are stored and used in aggregate to improve the service. (source) |
When to use which
Choose GPTZero when
- You need a probability for text that carries no statement about how it was written.
- You need plagiarism checks and sentence highlighting in the same report, or LMS integrations for a classroom.
- You want a long-standing tool whose published testing your institution already accepts.
Choose isGenAI when
- You want a finding you can quote: the sentence where an author or a tool says AI was used.
- You worry about false accusations and want a checker that never turns writing style into a verdict.
- You also need to check images for C2PA, AI labels or saved prompts, or code for declared Copilot use.
How to do the same job with isGenAI
- Paste up to 16,000 characters of writing or code into isgenai.com/ai-text-detector and choose the writing or code button.
- Read the findings: each one shows the sentence that declares AI use, such as “written with Claude”, or names a tool without claiming it wrote anything.
- Use declared statements as the basis for a conversation with the author, and compare them with drafts, commits or version history.
- If you need a probability that unlabelled text came from a model, use a classifier as a second opinion and treat its score as a lead, not proof.
Questions
Is isGenAI a free GPTZero alternative?
It is free and needs no account, but it answers a different question. GPTZero estimates whether text is AI-written; isGenAI finds declared AI use and shows the sentence. Many reviewers use a classifier for a lead and isGenAI for quotable evidence.
Why does isGenAI not give an AI percentage?
A style score cannot be traced to anything in the text, and GPTZero itself advises against using results alone to punish anyone. isGenAI reports only what the text states, so every finding can be checked.
Can isGenAI check images like an AI image detector?
Yes. The isGenAI image checker reads C2PA Content Credentials, IPTC digital source type labels and prompts saved by Stable Diffusion tools, free with no account.
Is isGenAI affiliated with GPTZero?
No. isGenAI is independent and not affiliated with GPTZero. Facts here come from gptzero.me as of October 2026.
Sources
Every statement about GPTZero comes from these pages, read as of October 2026. Products change; check the page before you rely on a detail. Product names belong to their owners and are used only to identify them.