Watermark PDF
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Put a word across every page, at whatever angle and however faint you want it, or add page numbers along the bottom. The watermark is drawn by your browser and embedded as a picture, which is why it can be written in any language your machine has a font for rather than only the handful a PDF supports on its own. The document never leaves the machine.
1 · Your PDF
2 · What to add
3 · How it looks
Use {n} for the page number and {total} for how many there are.
Frequently asked questions
Is my document uploaded?
No. Your browser reads the PDF, draws the stamp and writes a new file, all locally. The site’s security policy sets connect-src ‘none’, so the browser blocks network requests from these pages, meaning the document could not be sent even if the code tried.
Can the watermark be in Thai, or any other language?
Yes, and that is the reason it is drawn rather than typed. A PDF can use fourteen fonts without carrying one inside it, and all fourteen are Latin. Anything else means embedding a font file, which is hundreds of kilobytes. Instead the browser draws the word using the fonts already on your machine, and the result goes in as a picture. Whatever you can see in the box you can put on the page.
Why are page numbers done differently?
Because they are digits and they change on every page. Digits are among the fourteen fonts a PDF already knows, so a page number costs a few dozen bytes; drawing a picture for each one would cost several kilobytes a page to solve a problem numbers do not have.
Will the watermark cover the text underneath?
Only as much as you ask it to. The strength slider sets how solid it is, and 20 to 30 per cent is enough to read while leaving the document legible. The stamp goes over the page, so the text stays where it was and nothing is redrawn.
Can it be removed afterwards?
By someone with the right tool, yes. A watermark added this way is an extra layer on the page, not a change to the page itself, which is what makes it lossless and reversible. Treat it as a label saying how a document should be used, not as protection.