Add Watermark to PDF

Stamp custom text watermarks across all pages of your PDF document. 100% private in-browser tool.

Drag & Drop PDF to watermark

Files are never uploaded to any server

Choose PDF File

How to Stamp Watermarks on PDF Pages Online

Select Document

Drag and drop your PDF or pick it from local storage. The document parses locally in memory.

Format Typography & Angle

Customize your text (e.g. CONFIDENTIAL), choose 45° diagonal or 0° horizontal, and set opacity.

Download Stamped PDF

Click 'Stamp Watermark' to embed vector stamps across every page and download immediately.

100% Client-Side Privacy Architecture

Legal pleadings, business plans, patents, and sensitive contracts must never be uploaded to third-party web servers. FileVeda executes all PDF modifications locally using client-side JavaScript. Your files never leave your device.

FileVeda vs Legacy PDF Watermarkers

Compare our private, unlimited in-browser watermarker against commercial PDF tools.

Feature	FileVeda Watermarker	Cloud PDF Sites	Adobe Acrobat Pro
Document Privacy	100% In-Browser (Zero Uploads)	Uploaded to remote cloud server	Local (requires expensive license)
Page & File Size Limits	Unlimited (Device RAM Bound)	20MB / 10-page maximum caps	Unlimited
Vector Quality Preservation	100% Lossless Vector Stamping	Often downsamples images/fonts	Lossless vector
Alpha Transparency Blending	Precise 10%–100% Extended Graphic State	Coarse presets only	Supported
Pricing & Accounts	100% Free Forever, No Signup	Monthly subscription paywalls	$239.88/year subscription

Technical Guide: PDF Content Streams & Alpha Transparency Layers

Extended Graphic State (ExtGState)

ISO 32000-1 specifies how PDF renderers composite overlapping visual elements using alpha transparency:

Non-Stroking Alpha (ca): Controls the opacity value between 0.0 and 1.0 for vector fills and text outlines.
Blend Modes: The watermark is composited directly into the page layer hierarchy without rasterizing background vectors or corrupting searchable text.
Coordinate Centering: Automatic bounding box calculation ensures proportional placement across portrait, landscape, and letter-sized documents.

Legal & Audit Protection Best Practices

Watermarks establish chain-of-custody, restrict distribution rights, and deter unauthorized leaks:

45-Degree Diagonal Stamping: Spans across every paragraph and table, making screenshot theft or partial cropping immediately identifiable.
Red Crimson (#dc2626) Alert: Triggers immediate psychological awareness of confidential or restricted disclosure.
Permanent Content Injection: Injected as immutable drawing operators rather than an easily disabled HTML overlay.

Frequently Asked Questions

Can the watermark text be easily removed or selected by viewers?

FileVeda embeds the watermark directly into each page's PDF content stream with custom alpha blending, preventing casual removal in standard viewers.

Are my confidential contracts or manuscripts uploaded to a remote server?

Never. Document rendering and font vector stamping happen entirely client-side inside your browser via WebAssembly and PDF-Lib. Your files never touch external infrastructure.

What angle and opacity should I choose for 'CONFIDENTIAL' or 'DRAFT' watermarks?

A 45-degree diagonal angle with 20% to 30% opacity provides the ideal balance: high visibility across the entire page while keeping underlying text completely legible.