PDF Watermark & Page Numbers
Add custom watermark stamps or insert page numbers (header & footer) into your PDF.
Upload PDF to Add Watermark
Protect documents with diagonal or horizontal stamp text
How to Use PDF Watermark & Page Numbers
Upload PDF
Select the PDF file you wish to protect with a watermark.
Customize watermark
Enter text (e.g., CONFIDENTIAL, DRAFT), adjust opacity, color, angle, and size.
Apply & Download
Download your newly watermarked PDF document.
Key Benefits
- Custom opacity slider to prevent obscuring underlying text
- Preset watermark texts (CONFIDENTIAL, DRAFT, COPY, APPROVED)
- Client-side vector text rendering
Browser & Hardware Notes
- Image-based watermarks are planned for a future update; currently supports rich text watermarks.
Frequently Asked Questions about PDF Watermark & Page Numbers
How PDF Watermark & Page Numbers Operates Privately on Your Device
Unlike traditional cloud services that transmit your confidential files across the open internet to remote servers, SafeWebUtil operates on a strict zero-upload client-side architecture. Every transformation performed by PDF Watermark & Page Numbers executes exclusively within your browser's secure memory sandbox.
Lossless CosObject Tree Parsing
Parses and modifies low-level Cross-Reference (XRef) tables and CosObject streams via WebAssembly. Vector paths, Bézier curves, and TrueType fonts remain 100% crisp without destructive rasterization.
Isolated Browser Heap Memory
File bytes are read into transient ArrayBuffer allocations in local RAM. Background Web Workers manage garbage collection efficiently, supporting documents over 100MB with zero server exposure.
Strict Zero-Telemetry Privacy
Meets stringent compliance mandates (GDPR Article 32, HIPAA technical safeguards, corporate NDAs). Contracts, legal filings, and financial records never leave your machine.
Engineering Insights & Performance Best Practices for PDF Watermark & Page Numbers
Our PDF engine manipulates CosObject streams without canvas rasterization. Vector fonts, Bézier curves, and metadata remain intact. For large files over 100MB, close background browser tabs to maximize available RAM.
Related Tools
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Rotate individual pages or all pages of a PDF document by 90, 180, or 270 degrees.