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Add a watermark to a PDF

CONFIDENTIAL across every page — diagonal or tiled, as subtle as you like, stamped on your own device.

One PDF · watermarked on your device, nothing is uploaded

Runs in your browser. Files are never uploaded — you can go offline after the page loads.

How to use the Watermark PDF

  1. Drop one PDF.
  2. Type the watermark text, choose diagonal or tiled and the opacity.
  3. Download — every page carries the mark.

Easy to use

Drop files, pick options, download. Whole folders at once, no signup, no daily limit.

Best quality

The same engines the professionals use — SVGO, resvg, MozJPEG, libwebp, libavif — compiled to run in your browser.

Private & secure

Files are processed on your device and never uploaded. Close the tab and nothing remains anywhere.

Marking a document without wrecking it

A watermark has one job: to travel with the document. DRAFT stops an old version being mistaken for final; CONFIDENTIAL sets expectations before a page is read; a recipient's name turns any leak into an attributed leak — which is the real deterrent. The mark is drawn as translucent text on every page, so the document underneath stays sharp, selectable and searchable.

Tiled mode exists for when the watermark is doing protective work: dozens of small marks across the text are impractical to crop or clone out, where a single corner mark disappears with one crop. And because the documents people watermark are exactly the ones that shouldn't sit on a third-party server, the whole operation runs in your browser. For watermarking photos instead, use Watermark Images.

Frequently asked questions

Diagonal or tiled?

Diagonal is the convention — one big mark, instantly readable. Tiled repeats the mark dozens of times across the text itself, which makes cropping or cloning it out impractical; use it when the watermark is doing real protective work (proofs, pre-release documents).

Can the watermark be removed?

Honestly: a determined person with PDF software can remove a visible watermark — that is true of every watermark tool. Tiled at moderate opacity makes it genuinely tedious. For distribution control, watermark with the recipient’s name — the deterrent is attribution, not impossibility.

Your files never leave your device

Most online converters upload your file to a server. InfyTool ships the actual encoders to your browser as WebAssembly instead, so processing happens inside your tab — faster for batches, and nothing to delete afterwards.

  • No upload, ever. Turn off Wi-Fi after the page loads and every tool keeps working.
  • No limits. No file-size cap, no queue, no watermark, no account.
  • Runs on your CPU. Batches use several cores in parallel; nothing is throttled.

More free tools

Need icons or SVGs to start from?

InfyTool is built by the same team as these free libraries.