Online PDF Watermark Tool
Add text or image watermarks to PDF for free. Customize position, opacity, and rotation. Local processing for privacy.
How to Use
Select file
Start process
Local processing
Download result
Complete PDF Watermark Guide
Watermark Features
The PDF watermark tool adds custom watermarks to your PDF files, supporting both text and image watermarks. Text watermarks let you customize content, font size, color, opacity, and rotation angle; image watermarks support PNG/JPG logos. Watermarks can be applied to all pages or specific page ranges. Processing is entirely local in your browser. Common use cases: adding "CONFIDENTIAL" marks to prevent distribution, "DRAFT" labels for review documents, or personal/company logos for copyright protection. Watermark layer can be placed above (foreground) or below (background) content.
Processing Results
Privacy Protection
WebAssembly local processing means: files never leave your device, no network transfer, no server storage. Basic features work even offline.
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FAQ
Can I customize the watermark text, position, and opacity?
Yes. Allin PDF allows full customization: text content, font size (12-72px), rotation angle (-45° to 45°), opacity (10%-100%), and color. The watermark is applied diagonally across each page by default for maximum protection.
Is watermark addition done locally?
Yes, completely local. Watermark rendering happens in your browser via pdf-lib and Canvas API. Your document never leaves your device, ensuring complete confidentiality of sensitive files.
Process Documents Anywhere
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