About this tool
Add a diagonal text watermark — like CONFIDENTIAL, DRAFT or your name — across every page of a PDF. Choose between a repeating tiled pattern or a single centered stamp, and fine-tune the font size, opacity and color until it looks right.
The watermark is drawn locally with pdf-lib, so your file never leaves your device: nothing is uploaded, and the finished PDF downloads straight from your browser. Non-Latin watermark text (Cyrillic, Arabic, CJK and more) is supported too — it is rendered through a high-resolution canvas so every script displays correctly.
Watermarks are drawn on top of the existing page content and become part of the page, so they appear in every PDF viewer and when printing.
Frequently asked questions
Is my PDF uploaded anywhere?
No. The watermark is drawn onto the pages entirely in your browser with pdf-lib — your file never leaves your device.
Can I use non-English watermark text?
Yes. Text outside the basic Latin range is automatically rendered via a high-resolution canvas image, so Cyrillic, Greek, Arabic, Hebrew, CJK and accented characters all work.
What is the difference between tiled and centered?
Tiled repeats the watermark diagonally across the whole page in a grid pattern; centered places one diagonal stamp in the middle of each page.
Can the watermark be removed later?
It becomes regular page content, so casual removal is hard, but a determined user with PDF editing tools could still remove it — treat it as a deterrent, not as security.