Remove Anthropic's watermark from Claude text
Since August 2026 Claude embeds an invisible watermark in everything it writes. Paste your text: hidden characters are stripped exactly, and the wording is rewritten - the one thing Anthropic itself says the mark may not survive.
No credit card required
What actually gets removed
Two different problems. Only one can be solved exactly, and we are precise about which is which.
Zero-width characters
ZWSP, ZWNJ, ZWJ, word joiners and byte-order marks. No width, no glyph, and they survive copy-paste into any editor. Removed exactly.
Unicode tag characters
The U+E0000 block renders as nothing anywhere and can carry a whole hidden payload attached to ordinary letters. Removed exactly.
Variation selectors
A second steganographic carrier: invisible modifiers riding on plain letters. Removed exactly.
Exotic spacing
Non-breaking, en, em, thin and hair spaces that look identical to a space but are not one. Normalised to a plain space.
Typographic punctuation
Em dashes, curly quotes and single-codepoint ellipses — the punctuation a keyboard does not produce. Normalised to ASCII.
Wording and cadence
Signature vocabulary, scaffolding connectives, empty hedges and uniform sentence rhythm. Rewritten, not stripped — and rewriting is the one mechanism Anthropic names as degrading its watermark.
How it works
Three steps, and the first one is free.
Paste and scan
The scan is instant, free, and runs on exact character matching rather than a guess. You see every marker and its count before you spend anything.
Strip the characters
Every invisible and exotic codepoint is removed losslessly. No model is involved in this step, so nothing about your wording can drift.
Rewrite the tells
FckWatermark then makes the lightest rewrite that clears the wording and cadence markers. Facts, figures, quotes, structure and length stay put.
Built to change as little as possible
A tool that rewrites your text into something else has not removed a marker, it has replaced your writing. The character pass is exact and lossless. The rewrite pass is deliberately conservative: sentences carrying no marker come back verbatim, paragraph breaks stay where you put them, and word count stays within about ten percent. You can always see exactly what was found before you decide to run it.