Paste text. Find hidden Unicode characters.
Text Doctor is the fastest way to find and remove hidden Unicode characters and AI text watermarks from any text. AI writing systems can embed invisible characters — zero-width spaces, soft hyphens, variation selectors — to watermark generated content. Paste your text below to detect them instantly.
What do we detect?
Characters with no visible width. Common in AI-generated or copy-pasted web text.
U+200B (ZWS), U+200C (ZWNJ), U+200D (ZWJ), U+2060 (WJ), U+FEFF (BOM)
Unicode bidi control characters. Can reverse or override text rendering direction.
U+200E (LRM), U+200F (RLM), U+202A–U+202E (LRE/RLE/PDF/LRO/RLO), U+2066–U+2069 (LRI/RLI/FSI/PDI)
Tag characters in the U+E0000 block, used by AI text watermarking systems.
U+E0000–U+E007F (all flagged as TAG)
Invisible hyphenation hint. Affects line-breaking but is invisible in most renderers.
U+00AD (SHY)
Zero-width spaces (U+200B), soft hyphens (U+00AD), variation selectors, and tag-block characters are Unicode codepoints that render as invisible in most text editors and word processors but are preserved when copying text.
Some AI systems embed patterns of invisible Unicode characters — such as zero-width joiners or tag-block characters — into generated text. These patterns act as a fingerprint that persists through copy-paste, allowing the source to be identified even without image or metadata analysis.
Research watermarking systems (e.g. from academic labs) and some commercial deployments use Unicode-based techniques. The presence of unusual invisible characters in AI-generated text is a documented pattern even where formal watermarking is not confirmed.
Paste your text into Text Doctor and click "Fix" — the tool strips all detected hidden characters and copies the clean version to your clipboard.
Yes, entirely free. No account required. Text is processed locally in your browser and never sent to a server.