EDIT TOOL

Watermark PDF

Stamp a bold diagonal text watermark (such as CONFIDENTIAL, DRAFT, or COPY) across every page of your PDF document with customizable opacity levels.

HOW TO USE

Step-by-step guide

Step 1: Select your PDF document.
Step 2: Type your desired watermark text and select the opacity preset (Light, Medium, or Strong).
Step 3: Click "Add Watermark" to download your stamped PDF.

FAQ

Frequently asked questions

Is the watermark placed behind or in front of the page text?

The watermark is rendered over the page with translucent opacity so underlying text and diagrams remain readable.

Can the watermark be easily erased by recipients?

The watermark is embedded directly into the content stream of the PDF, requiring specialized vector editing tools to remove.

Can I customize the watermark text and font?

You can enter any custom alphanumeric string up to 80 characters, rendered in crisp Helvetica Bold.

PRIVACY & SECURITY

Client-side in-memory processing

PDF Toolbox is engineered with a strict browser-first architecture. All file operations execute entirely in your local browser sandbox via modern WebAssembly and JavaScript engines. No file bytes or sensitive document data are ever uploaded, buffered, or stored on external servers or cloud infrastructure. Memory buffers are cleared immediately when you finish or close your tab.

🔒 Zero server uploads: Processing stays on your device ⚡ Instant execution: No network upload/download queues 🛡️ Private & Confidential: Safe for legal, medical & financial files