About IsThisAiWritten

IsThisAiWritten is an independent, free AI detector. You paste text, it runs a detection model inside your browser, and you get a plain report. There is no account, no word limit and no upload.

Why it exists

Most AI checkers ask for an account, cap the length of what you can paste, or send your text to their servers. That is a poor fit for the people who need a quick answer most often: a student checking their own essay before handing it in, an editor with a 90,000-word manuscript, or someone who simply doesn't want a private document stored on a stranger's server.

We built the opposite. The detection model runs on your own device and does all its work there. Close the tab and your text is gone.

What you get

• Free, with no sign-up. No account, no email and no credit card. No credits, no daily cap, no paywall and no premium tier.
• No word or character limit. Paste a whole thesis or novel and check it in one go.
• Nothing is uploaded. The text never leaves your device; the check runs in your browser.
• Your text is never stored, shared, sold or used to train anything. We never receive it.
• Every word is scanned, never a sample.
• A report that explains itself: an AI-likeness score, sentence-by-sentence highlights, style notes with one-click plainer wording, a hidden-character and look-alike-letter cleaner, and a narrative fingerprint for fiction.
• Opens .txt and .docx files right in the browser.
• No ads where you paste text.

How it is tested

The detector is tested on a frozen set of human and AI texts, scored exactly the way your browser scores them. Its cut-offs are set per text length to keep false flags on human writing low, and the whole method is on the methodology page.

What we aim for is a free check that holds nothing back: no account, no limit on length, nothing uploaded, and a report that shows which passages and phrases drive the result.

Our promises

• Your text stays yours. There is nothing for us to collect: it never leaves your device.
• Every result explains itself. You see the outcome, how confident it is, and the passages and phrases behind it, never a bare number.
• The whole report stays free, with no paywalled sections and no upgrade button.

Who runs it

IsThisAiWritten is run by Luis, its founder, from Switzerland. How we write comparisons and articles, and how corrections work, is set out in our editorial policy. To reach us, write to contact@isthisaiwritten.com or use the contact page.

Research we build on

The narrative fingerprint for fiction draws on StoryScope (Russell et al., COLM 2026). The style explanations draw on published work on how language models write differently from people. The detection model is an open classifier released on Hugging Face under the MIT licence. We are not affiliated with any of these authors, nor with any company named on this site.