Add Watermark to PDF Securely (100% Free)

Easily add text, stamps, or image watermarks to your PDF files online. Processed entirely in your browser for absolute privacy—no server uploads required.

Why Choose Our PDF Watermarker Over Big Brands?

Most popular PDF tools compromise your privacy by forcing cloud uploads or lock basic features behind a paywall. We built an advanced, client-side editor that gives you premium features for free.

Zero Server Uploads

Your highly sensitive documents are processed locally in your browser's memory. No uploads, no downloads, complete immunity to data breaches.

Advanced Layering

A premium feature made free. Choose to place your stamp over the text or seamlessly insert it below the PDF content for a professional background look.

Pixel-Perfect Control

Select from 10+ professional fonts, use HEX color grids, and apply true mathematical rotation matrices for perfect diagonal stamps every time.

Ultimate Customization at Your Fingertips

Rich Text Formatting

Format your text exactly how you want it. Apply bold, italics, or underline styles. Choose from standard fonts like Arial, Courier, or Times New Roman, and pick exact brand colors using our extensive color grid.

Logo & Image Watermarks

Protect your intellectual property by stamping your company logo (PNG or JPG). Adjust the opacity so it doesn't distract from the main document.

Mosaic Pattern Engine

Need maximum security? Enable the 'Mosaic Pattern' to automatically tile your text or image repeatedly across the entire document page.

Specific Page Targeting

Don't want the watermark on every page? Use our exact page range selector to stamp only the necessary sections of your massive PDF documents.

How to Add a Watermark to a PDF Online

Securely stamp your documents in 4 simple steps.

  1. Upload PDF: Drag and drop your file into the secure, browser-side tool.
  2. Choose Type: Select 'Text' for words or 'Image' to upload your company logo.
  3. Customize: Set the font, color, rotation (e.g., 45 degrees), transparency, and layer position (Over or Below content).
  4. Add & Download: Hit the button to instantly process and download your stamped file securely.

Frequently Asked Questions

Is it safe to add a watermark to a confidential PDF here?

Absolutely. Unlike other big PDF platforms that upload your files to their cloud servers, our tool uses advanced WebAssembly to process your documents entirely locally inside your browser. Your files never leave your device, ensuring 100% data privacy.

Can I put the watermark text behind the PDF content?

Yes! This is one of our premium features available for free. Under the 'Layer Position' settings, simply choose 'Below Content'. Our algorithm will inject your text or image watermark directly into the PDF's background stream, keeping your main text perfectly readable.

Will adding a watermark reduce my PDF quality?

Not at all. We do not flatten or convert your PDF into images. We embed the watermark using native PDF-lib vectors, meaning your document retains its original high-resolution quality, and all existing text remains selectable and OCR-friendly.

Does this tool work on mobile devices?

Yes, our watermark tool is fully responsive. You can easily select fonts, pick hex colors, adjust transparency, and rotate your stamp directly from your smartphone browser without installing any app.