Scan text copied from Gemini for hidden Unicode characters, right in your browser. Private and free, since nothing ever leaves your device.
Gemini watermark detector
Paste in text copied from Gemini and this app scans it for zero-width and non-printing Unicode characters, the kind that take up a position in a string while showing nothing on screen. It's built around a specific search: does Gemini hide a watermark in its answers.
Everything runs on your device. There's no account, no upload and no cap on how much text you check.
Workflow
A routine check before anything from Gemini ships anywhere.
Why it matters
A zero-width space inside a pasted heading splits the keyword, so your slug or anchor stops matching the visible title. A non-breaking space picked up from a Google Docs export can break a shell command, a config file or a CSV column with no obvious cause.
The same characters cause broken find-and-replace, failed CMS saves, and layout problems in exported PDFs. Checking first turns a category of confusing bugs into a five-second fix.
Where they come from
Gemini sits inside Google's own tools, with one-click export into Docs and Sheets, and inline drafting inside Gmail. Each of those apps has its own typography engine that reformats punctuation and spacing as text moves through it, which is a common source of the non-breaking spaces and curly quotes a scan finds.
Copying straight out of the chat window is one path; copying out of an exported Doc is another, and the second tends to carry more of this kind of residue than the first.
Straight answer
No, and this app doesn't claim otherwise. The same characters show up in text copied from Word, plain Google Docs and other chat tools, so a finding is a formatting lead, not proof of where the words came from.
It also says nothing about whether the text would pass a separate AI detector, since those tools look at sentence patterns and word choice, not invisible bytes.
Who it's for
Anyone moving Gemini output into a place that parses text strictly, publishes it, or judges it.
Not a deliberate hidden marker. Text copied from Gemini, especially routed through Google Docs or Sheets, can carry ordinary invisible characters left over from those apps' own formatting.
Paste it above and press Scan text. Every hidden character found is listed along with where it sits.
Yes, with no limit on how many checks you run, since scanning happens on your own device.
No. The scan runs entirely in your browser. Nothing is sent to a server, stored or logged.
No. The same characters appear in text copied from Word, plain Google Docs and other AI tools. It's a formatting signal, not proof of source.
Docs auto-formats punctuation and spacing as part of its typography, converting straight quotes to curly ones and inserting non-breaking spaces in certain spots, regardless of what produced the underlying words.
No. It scans characters, not writing style, and makes no claim about which model produced the text.
No tool can promise that. Detectors weigh sentence patterns and word choice far more than invisible characters.
No. This tool only reports findings. Nothing is altered unless you run the separate cleaner.
Yes, the site's watermark remover strips flagged characters while keeping your wording exactly as written.
No. Since the scan runs on your device rather than a server, there's nothing to cap.
Yes. A zero-width space inside one splits the visible text from what a crawler or CMS actually parses.
Yes. Indentation and line breaks are preserved, and any zero-width characters breaking a build are flagged.
Yes, the characters are language-independent, though the zero-width non-joiner is meaningful in Persian and some Indic scripts and worth a closer look before you act on it.
Text routed through Docs, Sheets or Gmail commonly picks up invisible spacing and typography characters during those apps' own formatting, even when nothing looks off.
Not yet. For multiple documents, paste, scan and repeat for now.
Yes, since nothing leaves your device there's nothing to worry about sharing.
Yes, the layout and the scan both work the same on a phone browser.
The scan itself is identical. This page is aimed at people specifically searching for Gemini, since Google's own apps shape what gets left behind, not the underlying check.
Yes. The two follow different formatting paths, so the same underlying answer can carry different invisible characters depending on which one you copied from.
No, though you can. The app works fine offline once loaded, which is a quick way to confirm nothing is being sent anywhere while you scan.