PDF Utilities

Add Watermark to PDF

Protect confidential documents or stamp status markers (e.g. "CONFIDENTIAL", "DRAFT", "SAMPLE") onto your PDF pages.

100% Private · Runs locally in your browser 0 KB Uploaded

How Local Processing Works

1

Selected in Browser Memory

When you select or drop a file, your browser creates a temporary local Blob / ArrayBuffer pointer directly in your device's RAM.

2

Processed Client-Side

Our client-side engine (pdf-lib) processes the data directly using your computer or phone's CPU.

3

Saved Directly to Your Downloads

The resulting output is downloaded immediately to your device. When you close or refresh the tab, memory is cleared automatically.

Verify It Yourself

Open your browser's Developer Tools (F12 or Ctrl+Shift+I), switch to the Network tab, and convert any file. You will see zero network POST requests carrying file data.

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Click to browse or drop your PDF here

Select any PDF file · 100% in-browser processing

How to Watermark PDF Documents Online

Watermarking PDF files is essential for protecting intellectual property, marking preliminary drafts, or preventing unauthorized distribution of internal documents. FreeFileTool provides client-side watermarking that runs completely in your local browser without requiring file uploads.

Step-by-Step Instructions

  1. Select your document: Drop or select your PDF file.
  2. Customize watermark: Enter custom text (e.g. "DRAFT", "DO NOT COPY"), opacity, size, and rotation angle.
  3. Generate & Download: Click "Add Watermark & Download PDF" to save the stamped PDF to your computer.

Frequently Asked Questions

Does adding a watermark upload my PDF to a server?

No. All text overlay rendering and document modification take place inside your browser memory using pdf-lib. Your files never leave your device.

Can I adjust watermark transparency and angle?

Yes! You can set custom opacity (from subtle 10% to full 100%), font size, and rotation angle (e.g. 45° diagonal or horizontal).

Will watermarking alter the existing PDF text or formatting?

No, the watermark text layer is stamped on top of existing pages without modifying underlying vector graphics or text content.