PDF Watermark
Stamp text or image watermarks onto PDF pages.
PDF Watermark stamps custom text across every page of a document — CONFIDENTIAL, DRAFT, a client name — with a live preview so you see position, rotation, and opacity before you download. Controls cover nine anchors, color, opacity, rotation, font size, and margin. Output is watermarked_{original}.pdf written with pdf-lib in your browser.
The right pane updates as you type (debounced), and Prev/Next walks the document so you can check crowded pages. The tool does not store your file; watermarking is a pure local redraw of Helvetica text on each page.
How it works
After load, a single-page PDF.js preview renders the current page. Settings (text, position, color, opacity, rotation, font size, margin) feed a debounced preview that draws a translucent text overlay without mutating the source.
On download the tool reloads fresh bytes, embeds StandardFonts.Helvetica, and for each page computes the anchor from getWatermarkPosition, converts hex to RGB, then drawText with degrees() rotation and the opacity you chose. Reloading avoids painting twice on the same in-memory document.
How to use
- Open Add Watermark to PDF and drop or click a PDF (hint: Click or drag and drop your PDF here).
- Wait for Loading PDF… and the first-page preview; use Change File to swap documents.
- Enter watermark Text (default CONFIDENTIAL) — download stays disabled while empty.
- Choose Position (nine anchors; default Center), Color, and Opacity % (5–100, default 30).
- Tune Rotation (−180°…180°, default 45°), Font Size (12–150pt, default 40), and Margin (0–200, default 40).
- Click Prev / Next to confirm the mark on different pages.
- Click Download PDF and wait for Processing… (success toast: Watermark applied successfully!).
- Save watermarked_{name}.pdf from your browser’s download location.
Tips
- Keep opacity near 30% for subtle DRAFT marks; raise it only when the mark must dominate the page.
- Diagonal Center with ~45° rotation is the classic proofing look; Bottom Right suits approval stamps.
- Text is required — clear the field to disable download rather than exporting an empty stamp.
- Encrypted PDFs fail at read time with a clear error; unlock first if needed.
PDF Watermark FAQ
Does this upload my PDF?
No. Preview and stamping run locally with PDF.js and pdf-lib.
Can I watermark with an image logo?
This tool is text-only (Helvetica). For image marks, stamp externally or combine after export.
Why did download not start?
Empty watermark text disables the button. Enter at least one character.
What filename will I get?
watermarked_ plus the original filename, for example watermarked_report.pdf.
Does the watermark affect only visible pages?
It is drawn on every page in the document, not just the page you are previewing.