Runs locally · Zero uploads

PDF Watermark

Diagonal text watermark — all pages or specific ones.

How it works

Stamp DRAFT, CONFIDENTIAL, INTERNAL, or any custom text across every page of a PDF. The watermark is drawn as real PDF text (Helvetica embedded), not a raster overlay, so file size stays small and the result is searchable + accessible.

Verify it yourself. Open DevTools → Network → run a conversion. The only requests you'll see are the page assets — your file never leaves this tab.
On mobile? Downloaded files save to your Files app (iPhone/iPad) or Downloads folder (Android). On iPhone, you can also check the Downloads button in Safari's toolbar. This is how all browser downloads work — not a Bytario limitation.

FAQ

Can I add an image watermark instead of text?

V1 supports text watermarks only. Image overlays are coming in a future release; for now use a vector-text logo or rasterize an image into a PDF first.

Will the watermark be removable?

It is drawn into the page content stream, so casual users cannot remove it via Acrobat. A determined attacker can extract pages or re-OCR; if you need cryptographic non-removability, use a digital signature instead.

Does this work on every page?

By default, yes. Use the API directly if you need to watermark only specific pages.

Use via API

Need to automate this? The same engine is available as a REST API at api.bytario.com.

curl "https://api.bytario.com/v1/pdf/watermark?text=CONFIDENTIAL&opacity=0.3" \
  -H "Authorization: Bearer $BYTARIO_KEY" \
  --data-binary @doc.pdf \
  --output stamped.pdf

POST /v1/pdf/watermark — full docs · pricing from $9/mo