ChatGPT Watermark Detector
There is nothing statistical to detect in ChatGPT text right now, so this page checks what is actually in the paste: hidden characters, clipboard fragments and lookalikes.
- Watermark type
- None confirmed
- Hidden characters
- No
- Official detector
- Unsupported: None
- DetectMark support
- DetectMark support: Hidden characters only
- Removal
- Hidden Unicode removable where present
Detector or classifier
The difference decides whether a result means anything. A watermark detector reads a signal the model deliberately embedded, using a key. A classifier guesses from writing style and returns a score.
Only one of those can be wrong in a way that ends someone's semester. Scores get treated as evidence, and the false-positive rate is invisible to the person reading the number. DetectMark reports what is in the file or the text and nothing else.
What comes back for a ChatGPT paste
Hidden characters, clipboard HTML fragments and lookalike letters each get Clean or Found, with code points and positions for anything found. The statistical row reads Unsupported for OpenAI rather than Unknown, because there is no deployed mark to be uncertain about.
For ChatGPT images
Switch to the Image tab and the same honesty applies at the file level. Content Credentials, EXIF, XMP and PNG text chunks are parsed and listed. The pixel watermark row reports Unsupported, because verifying it needs Google's detector rather than a browser.
FAQ
No. OpenAI has not deployed a text watermark as of August 30, 2026. Any tool that claims to score ChatGPT text for a watermark is running a stylistic classifier.
The image tool reads the C2PA Content Credentials in the file and reports them. Pixel-level verification is not exposed as a public API, so that row reports Unsupported.
Not as a watermark. The o3 and o4-mini U+202F quirk in April 2025 was a training artifact and was patched.
Hidden Unicode, clipboard HTML fragments and lookalike letters, all in this browser tab.
AI detectors classify by style and return a likelihood. This checks what is actually present in the text or the file, and reports evidence rather than a guess.
Every check runs in your browser: how it works. The limits are written down too: what DetectMark cannot remove.