How to use this tool
Add PDF Watermark
What this tool does
Add PDF Watermark stamps custom text — CONFIDENTIAL, DRAFT, SAMPLE, or your company name — diagonally across every page. Watermarking discourages unauthorized sharing and marks document status before distribution.
Unlike cloud watermark tools that upload your contract or draft, this runs locally with pdf-lib. Adjust opacity, font size, and angle before converting.
Supported formats
Input: standard PDF (.pdf). Output: watermarked PDF with text overlay on every page.
Options: watermark text, opacity (10–80%), font size (24–96 pt), angle (0°, 45°, or 90°).
Step-by-step
Step 1: Upload your PDF.
Step 2: Enter watermark text (default: CONFIDENTIAL).
Step 3: Adjust opacity — 25% is readable but not obstructive for review copies.
Step 4: Click Convert and download the watermarked PDF.
Limitations & tips
Text watermark only — no image logos yet. Does not prevent determined removal (rasterize first for stronger protection). Password-protected input PDFs fail.
Watermark is drawn on top of content — very low opacity may be invisible on dark backgrounds.
Common use cases
Draft review: mark contracts DRAFT before client eyes.
Internal docs: stamp CONFIDENTIAL on HR policies.
Design previews: SAMPLE on mockups sent to stakeholders.
Privacy & local processing
Document Converter never uploads your file for conversion. Processing uses JavaScript in your browser tab — the same security boundary as editing a document offline. Closing the tab clears the in-memory copy unless you saved the output.
We may load analytics or ads when you visit the site, but those requests do not include your document bytes. For HR records, medical forms, or unreleased designs, local conversion avoids the third-party upload step that cloud converters require.
Browser-local vs cloud upload
Cloud tools like Smallpdf and iLovePDF receive your file via HTTP upload, process it on their servers, and return a download link. That model is convenient for public PDFs but adds privacy and compliance risk for sensitive content.
Document Converter runs pdf-lib, PDF.js, Mammoth, SheetJS, or Tesseract.js directly in your browser. Open DevTools → Network while converting: you should see no POST containing your file. You trade server-side CPU for device-side privacy — often the right choice for personal and workplace documents.