PDF operations Watermark

Watermark PDF

Add a diagonal text watermark to every page. Configure text, opacity, font size, angle, and colour — runs entirely in your browser via pdf-lib.

Local No upload pdf-lib

1) Select a PDF

Drop a PDF here, or click to browse.
Single file · browser-native processing

2) Configure watermark

Positive = counter-clockwise. 45° is the classic diagonal.
Phase
Select a PDF to begin.

Notes

  • The watermark is drawn as a text layer centred on each page — it's part of the PDF content, not a separate overlay.
  • Font: Helvetica (built-in PDF standard font, no external download required).
  • Opacity 0.15–0.25 is visible without obscuring underlying content.
  • Password-protected PDFs will fail — unlock them first.