ConvertWarp

Add watermark

Draw the same words across every page.

PDF tools use pdf-lib (MIT).

About this tool

A text watermark is a diagonal line of words drawn on every page — DRAFT, CONFIDENTIAL, a name. This tool uses Helvetica, up to 80 characters, at a fixed gray and angle. It is a visible stamp, not a forensic metadata tag.

It is also not a signature and not encryption. For an open password use Protect PDF. For a picture on the last page use Sign PDF.

pdf-lib draws the same Helvetica string on each page in the browser. 50 MB. Encrypted PDFs are not opened. Custom fonts, logos, and per-page text are not in v1.

How to watermark a PDF

  1. Choose the PDF you want stamped with a short line of text.
  2. Type the watermark (80 characters or fewer).
  3. Apply and download.

50 MB, 80 characters, Helvetica, one string for the whole file. Password-protected inputs refused.

FAQ

Is the PDF uploaded to stamp it?
No. Drawing happens in this tab.
Can I use my own font or logo?
Not here. Sign PDF places a PNG or JPEG on the last page if you need a mark that is a picture.
Can someone remove it?
A determined editor can. This is a visible overlay, not DRM.
Does it flatten the PDF?
It draws on top of existing pages. It does not rasterize them.
Non-Latin text?
Helvetica does not cover every script. Unsupported glyphs may fail or omit.

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