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PortuguêsFree AI detector: written by a person or by AI?
Paste a text and get the AI probability, which paragraphs look most suspicious and the signals that explain it. No guesswork, no black box.
Paragraph-level analysis
See which parts of a mixed text look AI-written.
Several languages
Spanish, English, French, Italian, Galician and Portuguese.
Visible signals
Regularity, typical phrases, vocabulary and tone: you will know why.
Paraphrasing and tricks
Flags invisible characters, disguised letters and forced synonyms.
How it works
Paste or upload your text
Type, paste or upload a file (.txt, .docx…). No sign-up needed to try it.
It is analyzed instantly
We measure statistical signals in the text, paragraph by paragraph, in your language.
Review the result
You get the overall percentage, the most suspicious paragraphs and the signals that explain it.
Who is it for?
Students
Check your own work before submitting and see which parts sound “templated”.
Teachers
A rough second opinion to start a conversation, never definitive proof.
Writers and agencies
Check contributors’ texts and spot generic passages worth rewriting.
Editors and media
Quickly screen outside submissions and decide what deserves a closer look.
An example result
Illustrative example with made-up data; not a real result.
Try it with your textA free AI content detector that shows its reasoning
ZeroAliens is an AI text detector: paste a text and it estimates how likely it is to have been written by ChatGPT or another AI writing tool. Instead of a single score, it checks every paragraph and shows the signals behind the result, such as sentence regularity, typical AI phrases and predictable vocabulary, so you can judge for yourself. It analyzes texts in Spanish, English, French, Italian, Galician and Portuguese.
Frequently asked questions
How does the AI detector work?
It measures statistical patterns in the text, such as how regular the sentences are, how predictable the vocabulary is and how many typical AI phrases appear, and combines them into a probability for the whole text and for each paragraph.
Can it tell if a text was written by ChatGPT?
It estimates whether a text looks AI-written, as texts from ChatGPT and similar tools often do. It cannot tell which tool wrote it, and the result is an estimate, not proof.
Is the AI checker accurate? Can it give false positives?
No detector is 100% accurate. Formal or very polished human texts, and texts by people writing in a second language, can be flagged by mistake, and edited AI text can go unnoticed. Use the result as one clue, never as the only evidence against a person. Accuracy has been measured mainly on English; other languages are less validated.
Which languages does it support?
Spanish, English, French, Italian, Galician and Portuguese. The language of the text is detected automatically, and longer texts give more reliable results.
Is it free?
Yes. For now the service is free, with no word limit on a free account; it may become paid in the future.