Watermark Features How It Works FAQ
verified_user 100% Browser-Based & Secure

Add Watermark to PDF
Without Uploading

Protect your PDFs with text or image watermarks — processed entirely in your browser. Your files never leave your device.

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PDF Watermark

Select a PDF, customize your watermark, position it, and save.

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Select PDF file Tap to choose a PDF
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Position & Transform
CONFIDENTIAL
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Drag corner handle to resize/rotate

opacity Opacity: 24%

Why Use This PDF Watermark Tool?

The most secure way to add watermark to PDF online

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100% Client-Side

Your PDF never leaves your device. Everything is processed locally in your browser.

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Text Watermark

Use presets or custom text. Configure color, size, opacity, and rotation.

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Image Watermark

Stamp your logo or any image. PNG transparency supported.

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Interactive Editor

Drag to move, handle to rotate & scale — like the UniDoc app.

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Tile Watermark

Repeat across every page with configurable spacing.

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Lightning Fast

Modern browser APIs. Large PDFs in seconds.

How to Add Watermark to PDF

Same flow as the UniDoc app — right in your browser

1

Select PDF

Choose your PDF file. It stays on your device.

2

Choose Text or Image

Pick a preset, type custom text, or upload your logo.

3

Position & Customize

Drag, rotate, and scale on the interactive preview.

4

Save & Download

Click save and download your watermarked PDF.

The Best Free PDF Watermark Tool Online

Looking for a reliable way to add watermark to PDF online? UniDoc's free PDF watermark tool lets you protect your documents without compromising privacy. Unlike other services, our watermark adder to PDF processes everything in your browser — your files never leave your device.

Whether you need to stamp "CONFIDENTIAL" on business documents, add your company logo to reports, or mark drafts before sharing, this tool handles it all with the same interactive editor found in the UniDoc mobile app.

Frequently Asked Questions

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

Yes. Everything runs in your browser using JavaScript. Your PDF is never uploaded to any server.

Can I use my logo as a watermark?

Yes! Switch to Image mode and upload a PNG or JPG. PNG with transparency works best.

Can I drag and position my watermark?

Yes. The interactive editor lets you drag to move, and use the corner handle to rotate and scale — exactly like in the UniDoc app.

Is there a file size limit?

The web tool supports PDFs up to 500 MB.

Is this tool free?

Yes, completely free with no registration. For more features, try the UniDoc app.

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