Stamp PDF Online

Brand or protect documents with a visible stamp on every page.

Quick Summary: Stamp PDF Online

Brand or protect documents with a visible stamp on every page. Siliph runs in your browser with encrypted uploads and a built-in AI assistant for portal-specific settings.

What does Stamp PDF Online do?

Brand or protect documents with a visible stamp on every page. Watermark PDF overlays diagonal or centered text and logo images across pages—marking drafts, branding deliverables, or discouraging unauthorized copies.

When to use Stamp PDF Online

You need to stamp pdf online quickly without installing apps
The file contains sensitive data and you prefer local processing

Law firms label drafts "PRIVILEGED AND CONFIDENTIAL" before circulation; agencies stamp "SAMPLE" on training PDFs; photographers embed subtle logos on proofs. Watermarks signal status without hiding underlying content.

Siliph Watermark PDF lets you set opacity, rotation, font, and tile spacing in the browser so watermarks stay readable on screen but do not obliterate tables. Image watermarks support PNG logos with transparency.

Tiled watermarks repeat across large architectural sheets where a single corner mark could be cropped out. Lighter opacity preserves OCR accuracy when you still need searchable text beneath the stamp.

Encrypted uploads protect unreleased creative work during processing. Files auto-delete within two hours on the free tier, and watermarking requires no Siliph signup.

Use Protect PDF alongside watermarks when you must also block editing, or Flatten PDF to bake watermarks into a non-interactive snapshot for clients.

Siliph security tools—password protection, unlocking, redaction, and watermarks—process inside an encrypted browser session so sensitive PDFs stay protected in transit. We delete your files within two hours on the free tier and never gate basic protection behind signup.

Visual Guide

How Watermark PDF works

This interactive preview demonstrates the interface layout and processing controls you will find in our workspace above. Everything is designed to be fast, responsive, and completely secure.

Runs completely inside your browser

AES-256 secure encryption

Automated file clean-up within 2 hours

siliph.com/watermark-pdf

CONFIDENTIAL

Text stamp

Opacity (30%)

Secure SSL WorkspaceLocal Browser Preview

How to add a watermark to a PDF — step by step

Follow these detailed steps to complete your task securely in the cloud.

Upload PDF

Select the document you want to stamp with a watermark.

Upload PDF

Define watermark content

Type custom text (e.g., 'CONFIDENTIAL') or upload a logo image.

Adjust rotation & opacity

Customize rotation angles and transparency percentage limits.

Opacity: 30%

Download file

Permanently write the watermark stamp onto pages and download.

Key Features & Benefits of Watermark PDF

Discover why thousands of professionals trust Siliph for fast, high-quality document editing and conversion.

AI Tool Assistant

Built-in AI suggests optimal settings and answers questions for every PDF tool.

AES Encryption Shield

Password-protect documents to restrict viewing or unauthorized opening.

Print & Copy Restrictions

Set password permission rules to lock file printing, editing, and copying.

Static Flattening

Flatten interactive form fields and digital signatures to prevent tampering.

Frequently asked questions about Watermark PDF

Brand or protect documents with a visible stamp on every page. Siliph is free to start — no signup required.

No. The tool runs in your browser on phone, tablet, or desktop.

Yes. Siliph lets you use Watermark PDF for free. The free plan includes 3 tasks per hour with files up to 50 MB or 50 pages. Paid plans remove these limits and add priority processing.

Yes. Files are transferred over an encrypted HTTPS connection, processed automatically without human access, and deleted from our servers within 2 hours on the free plan.

No. Watermark PDF runs entirely in your web browser and works on Windows, Mac, Linux, Android and iOS. There is nothing to download or install.

Embed this tool on your site

Add Watermark PDF to your blog or website for free. The embed includes a dofollow backlink to Siliph when you use the attribution snippet below — that helps both sites rank.

Embed (iframe)

<iframe src="https://siliph.com/stamp-pdf-online?embed=1" title="Watermark PDF — Siliph" width="100%" height="620" style="border:0;border-radius:12px;max-width:900px;" loading="lazy" allow="clipboard-write"></iframe>
<p style="font-size:12px;color:#666;margin-top:8px;"><a href="https://siliph.com/stamp-pdf-online" title="Watermark PDF — Siliph" rel="dofollow">Watermark PDF</a> powered by <a href="https://siliph.com/" title="Siliph — Free PDF Tools" rel="dofollow">Siliph</a></p>

Link for blog posts / tool lists

<p style="font-size:12px;color:#666;margin-top:8px;"><a href="https://siliph.com/stamp-pdf-online" title="Watermark PDF — Siliph" rel="dofollow">Watermark PDF</a> powered by <a href="https://siliph.com/" title="Siliph — Free PDF Tools" rel="dofollow">Siliph</a></p>

Direct link: https://siliph.com/stamp-pdf-online