Free forever · Runs in your browser
Sign it once. Prove it anywhere.
Paste your text and sign it. From then on it carries your name into every email, portal and shared doc, and it still points back to you after every hidden character is stripped out. Signing is free. Verification is free. Your text never leaves this page, because signing runs in your browser.
A fresh signing key (Ed25519) is created in your browser each time you sign, so nothing about you is stored anywhere. Longer text (roughly 50+ words) carries the invisible watermark; short text still gets fingerprints.