Secure Your PDFs with Custom Watermarks
Sharing a draft for review? Sending a confidential contract? Stamping your documents with a watermark is the best way to prevent unauthorized use and declare ownership.
Instant Typesetting
Type your text (e.g., "DRAFT", "CONFIDENTIAL", "URGENT") and watch it appear instantly on your document preview.
Full Customization
Adjust the opacity to make it subtle so it doesn't block reading. Rotate it 45 degrees for that classic stamp look. Change color and size to match your brand.
Permanent Seal
Once applied, the text is baked into the PDF layers. It cannot be easily removed by selecting text, providing a layer of security.
Why Client-Side Watermarking?
To watermark a file on most other websites, you have to upload it. That means you are sending your confidential "DRAFT" or "INTERNAL ONLY" documents to a stranger's server.
Zero-Trust Security
With Andromeda PDF, the watermark processing code runs directly in your browser. Your secret documents never travel across the internet. You stay 100% in control.
Technical Insight: Stream Injection
We don't just "overlay" an image. We inject a new Content Stream directly into the PDF's internal object graphic state.
By appending a new operator sequence (defining font transparency, rotation matrix, and text positioning) to every Page Object, the watermark becomes an intrinsic part of the document structure. This ensures it renders crisply at any zoom level and prints perfectly, unlike generic image overlays.
Best Practices
Design
Use a light grey color with 30-50% opacity. This ensures the text behind it is still readable.
Placement
A diagonal watermark across the center is hardest to crop out or ignore.