Free tools / Text watermark signal checker
Text watermark signal checker: what is hidden in this text?
Our text watermark signal checker lists the characters and patterns some generators and editors leave in text: zero-width and other invisible characters, unusual spaces, typographic punctuation, letters from another alphabet inside a word, and links tagged with an assistant's name. It shows where each one sits and never claims to say who wrote the text.
The check runs in this page. Nothing you enter is sent to our server. Paste up to 100,000 characters.
No email is needed, and nothing you paste is stored. A shared result stays in its link, not on our server.
What we check and why
Invisible characters
Zero-width spaces and joiners, word joiners, byte order marks, bidirectional controls, soft hyphens, tag characters, variation selectors, control characters and private-use characters, each with its line, column and code point.
Unusual spaces and punctuation
Non-breaking and narrow spaces, en and em dashes, curly quotes, ellipsis and bullet characters. They are visible but differ from what most keyboards type.
Mixed-script words
A word that mixes Latin letters with Cyrillic or Greek ones, such as a Cyrillic a inside an English word. It looks the same and reads as a different word to search and matching.
Links tagged with an assistant's name
Links whose utm_source names an assistant, which some assistants add to links they show.
What it cannot tell you
Finding these does not show who or what wrote the text, and not finding them does not show a person did. Statistical watermarks that some providers describe sit in word choice and need the provider's own detector, so we do not test for them.
Questions
Can this tell whether AI wrote a text?
No. It finds characters and patterns in the text. Editors, keyboards and web pages add many of them too, so finding them does not show who or what wrote the text, and not finding them does not show a person did.
Do AI tools add invisible watermarks to text?
Text can pick up invisible characters on its way through generators, editors and copy and paste, and some providers describe statistical watermarks in word choice. Statistical watermarks need the provider's own detector, so this check does not test for them.
What is a mixed-script word?
A word that mixes letters from two alphabets, such as a Cyrillic a inside an English word. It looks identical on screen, but search, spell-check and matching treat it as a different word.
Want the fix made for you?
Answer Repair completes one agreed source-backed page or fix. Choose Live or Handoff before payment. Due 48 elapsed hours after Ready. Full refund on request within 30 days of delivery.
When you want us to do the work, every offer and its published price is on our offers page. More free checks: the ChatGPT Business Hub readiness check, the text cleanup tool and the local file analyzer, or see all free tools.