Choose a file to convert. It's processed locally — never uploaded. Tip: add several files to convert them all at once.
{ } How it works
What it is
Stamp diagonal text (e.g. "CONFIDENTIAL") across every page.
How it works
Add Watermark to PDF works on the file you upload. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.
Inputs
- PDF file — upload a file (.pdf); it is read locally in your browser
- Watermark text — a value (default: "CONFIDENTIAL")
- Opacity (0–1) — a value (default: "0.2")
- Font size — a value (default: "48")
- Angle — a value (default: "45")
Output
PDF text — copy or download it from the Output panel.
{ } FAQ
Is my data uploaded to a server?
No. Everything runs locally in your browser — your files never leave your device.
Can I process more than one file at once?
Yes — add several files and they’re all processed and downloaded together as a ZIP.
Is this tool free?
Yes — it’s completely free and needs no sign-up.