Mark your documents.
Protect your content.
Add a diagonal text watermark to every page — CONFIDENTIAL, DRAFT, SAMPLE, or any custom text. Fully in your browser.
Free · No account · No upload
Drop your PDF here
PDF files only — processed entirely in your browser
Three steps. Every page watermarked.
Upload your PDF
Drop your PDF onto the upload area or click Browse PDF to select it from your device.
Set watermark
Choose a preset (CONFIDENTIAL, DRAFT, SAMPLE) or type custom text. Adjust colour, opacity (5–60%), and size.
Download
Click Add Watermark. The text is drawn diagonally across every page in your browser — download instantly.
Choosing the right opacity
Barely visible — for light indication without disrupting readability.
Visible enough to deter copying but light enough that content remains fully readable.
Hard to miss — good for DRAFT or CONFIDENTIAL documents where the mark must be obvious.
Very strong — for preview documents or samples where the content should be clearly marked.
How the watermark is applied
pdf-lib loads your PDF in the browser, then draws your watermark text diagonally across the centre of each page. The text is rendered in Helvetica Bold with your chosen colour and opacity. Because it is drawn at the PDF content level, the watermark is visible in all standard PDF viewers without any plugins. Nothing is uploaded to a server at any point.
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